Patent Publication Number: US-2021189340-A1

Title: Cancer-killing cells

Description:
The present invention relates to a cell-based therapy suitable for treating cancer. 
     Cancer is a leading cause of morbidity and mortality worldwide, with an annual increase in cancer incidence in developed countries. The World Health Organisation stated that in 2012 alone there were approximately 14 million new cancer cases (and 8.2 million associated deaths), with a projected rise to 22 million cases over the next two decades. Current therapeutic strategies include combinations of surgery, radiation, and cytotoxic chemotherapy, however many of these treatments are ultimately ineffective and associated with harmful side-effects. 
     Safety and efficacy has been assessed for Hematopoietic Stem Cell Transplantation (HSCT) as a therapeutic technique for treating certain cancers, such as Renal Cell Carcinoma. However, this treatment is still largely seen as experimental due to potentially fatal safety issues, with recipients exhibiting severe Graft vs. Host Disease (GVHD) as a result of the uncontrolled multiplication of pluripotent stem cells. Thus, there is a need for improved and alternative cancer therapies. 
     In spite of the increased cancer incidence, it has been observed that approximately 50-60% of individuals do not develop cancer in their lifetime. Indeed, in rare cases, some individuals exhibit spontaneous cancer regression. This observation has led to the study of white blood cells from spontaneous regressor individuals, and use of said white blood cells in Leukocyte Infusion Therapy (LIFT). 
     Conventional LIFT is carried out using apheresis for direct transfer of granulocytes (e.g. neutrophils) taken from the donor to the cancer patient. The current approach is not practical or scalable for use as a credible cancer therapeutic. First, granulocytes such as neutrophils have a very limited shelf-life (typically less than 24 hours) making them difficult to store. Secondly, apheresis requires approximately 5 (very rare) donors in order to acquire the required cell volume. Thirdly, to avoid an immune response from repeat exposure, the same donors cannot be used in a subsequent administration, thus requiring an increased pool of appropriate donors. Fourthly, it cannot be realistically expected that donors will be available on request, or willing to provide an endless source of granulocytes for the LIFT procedure. Fifthly, cancer killing efficacy of donor-derived granulocytes varies over time resulting in inconsistent therapeutic results. 
     As of yet, no viable alternative to conventional LIFT has been provided, nor has there been provided a solution to the associated problems. Thus, conventional LIFT is not viable as a scalable, safe, and reliable therapeutic technique. 
     The present invention provides a solution to at least one of the problems described above. 
     The present inventors have surprisingly found that it is possible to select for haematopoietic cells that are capable of differentiating into granulocytes having the ability to kill cancer cells. Once such a haematopoietic cell has been selected from a donor, said cell can be either stored for subsequent therapeutic purposes, or used directly as a medicament, for example in the treatment of cancer. Advantageously haematopoietic cells obtainable by a method of the invention can be immortalised thus providing a stable cell line that can be stored and/or propagated indefinitely. The present invention thus reduces the need for multiple rare donors, and/or for direct transfer of granulocytes collected from a donor to a cancer patient. Thus the invention provides a viable, scalable, safe and/or reliable therapy. 
     For the first time, the present inventors have shown that the cancer killing efficacy of granulocytes (e.g. neutrophils) is genetically-defined, rather than epigenetically-defined. This is demonstrated in Example 19, which shows that granulocytes derived from haematopoietic cells (e.g. haematopoietic stem cells) isolated from a donor have similar cancer killing efficacy to mature granulocytes isolated directly from the same donor. 
     Advantageously, donors found to have granulocytes with a high cancer killing activity can be used as a source of haematopoietic cells (e.g. haematopoietic stem cells) which can be differentiated into granulocytes with similarly high cancer killing activity. 
     Such haematopoietic cells can advantageously be stored, and used for the production of high volumes of granulocytes for use in treating cancer, thus overcoming problems of isolating sufficient quantities of fresh granulocytes from a donor. 
     Furthermore, the haematopoietic cell derived granulocytes have been found to kill cancer cells more rapidly than granulocytes isolated from a donor. In addition, haematopoietic cell derived granulocytes may have better cancer killing efficacy than fresh donor derived granulocytes (e.g. against pancreatic cancer cells). 
     Pancreatic cancer is known to be one of the most difficult cancers to treat. However surprisingly, the present inventors have succeeded in isolating granulocytes, and haematopoietic cells that differentiate into granulocytes, that have particular efficacy against pancreatic cells. 
     In one aspect the present invention provides an in vitro cell culture of haematopoietic cells, wherein said haematopoietic cells differentiate to form granulocytes characterised by:
         a. a surface potential defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec (or at least 1.0 μm·cm/volt·sec, for example at least 1.25 μm·cm/volt·sec, 1.5 μm·cm/volt·sec, or 1.75 μm·cm/volt·sec); and   b. the ability to kill cancer cells.       

     In a related aspect the invention provides a method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. measuring a surface potential of a granulocyte cell obtainable from a donor; and   b. selecting a haematopoietic cell from said donor when the measured surface potential is defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec (or at least 1.0 μm·cm/volt·sec, for example at least 1.25 μm·cm/volt·sec, 1.5 μm·cm/volt·sec, or 1.75 μm·cm/volt·sec).       

     The term “obtainable” as used herein also encompasses the term “obtained”. 
     The invention provides a method for selecting a haematopoietic cell comprising: measuring a surface potential of the haematopoietic cell; and selecting a haematopoietic cell that can be differentiated into a granulocyte that is suitable for treating cancer. Thus, in one aspect there is provided a method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. measuring a surface potential of the haematopoietic cell; and   b. selecting a haematopoietic cell that has a greater (e.g. more positive) surface potential than an otherwise identical haematopoietic cell that differentiates to form a granulocyte having a surface potential defined by an electrophoretic mobility of less than 2.0 μm·cm/volt·sec (or less than 1.0 μm·cm/volt·sec) and/or has a reduced ability to kill cancer cells.       

     A related aspect provides use of a surface potential of a haematopoietic cell, for selecting a cell that can be differentiated into a granulocyte that is suitable for treating cancer, wherein the surface potential is greater (e.g. more positive) than the surface potential of an otherwise identical haematopoietic cell that differentiates to form a granulocyte having a surface potential defined by an electrophoretic mobility of less than 2.0 μm·cm/volt·sec (or less than 1.0 μm·cm/volt·sec) and/or has a reduced ability to kill cancer cells. 
     The invention provides an in vitro method for selecting a subject for treatment (e.g. a subject that will benefit from a medicament described herein), said method comprising:
         a. admixing a granulocyte from said subject with a cancer cell line;   b. incubating said admixture;   c. measuring the % of cancer cells killed in said admixture; and   d. selecting a subject for treatment with an in vitro cell culture of haematopoietic cells, or a granulocyte, or an in vitro cell culture of granulocytes, or a pharmaceutical composition of the invention, when the granulocyte from said subject kills less than 5% of the cancer cells in the admixture (suitably when the granulocyte from said subject kills less than 60%, preferably less than 80% or 90%, of the cancer cells in the admixture).       

     In some embodiments a subject is selected for treatment with an in vitro cell culture of haematopoietic cells, or a granulocyte, or an in vitro cell culture of granulocytes, or a pharmaceutical composition of the invention, when the granulocyte from said subject kills less than 20% or 10% of the cancer cells in the admixture. Preferably a subject is selected for treatment with an in vitro cell culture of haematopoietic cells, or a granulocyte, or an in vitro cell culture of granulocytes, or a pharmaceutical composition of the invention, when the granulocyte from said subject kills less than 5% or 1% of the cancer cells in the admixture. 
     The in vitro method may also be used to monitor the ability of a subject&#39;s granulocytes to kill cancer cells. 
     In one aspect the invention provides an in vitro method for obtaining a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. contacting a cancer cell line with a granulocyte obtainable from a donor to form a test sample, and incubating said test sample; and   b. obtaining a haematopoietic cell from a sample from said donor when the % of cancer cells killed in the test sample is greater than the % of cancer cells killed in a control sample, wherein the control sample comprises a cancer cell line of the same type and a granulocyte obtainable from a different donor.       

     The % of cancer cells killed in a control sample may be determined either prior to carrying out the present method or at the same time as carrying out the present method (preferably at the same time). 
     For example, in one embodiment said method comprises:
         a. contacting a cancer cell line with a granulocyte obtainable from a first donor to form a test sample;   b. contacting a cancer cell line of the same type with a granulocyte (e.g. control granulocyte) obtainable from a different donor to form a control sample;   c. incubating said samples; and   d. obtaining a haematopoietic cell from a sample from said first donor when the % of cancer cells killed in the test sample is greater than the % of cancer cells killed in the control sample.       

     In some embodiments the method may comprise the use of a plurality of different test samples comprising granulocytes from further donors (e.g. second, third, fourth donors, etc.). 
     The control sample referred to may be a sample from a donor that has granulocytes that do not kill cancer cells (e.g. granulocytes that do not kill at least 5% of cancer cells in a method described herein). In other embodiments, the control sample referred to may be a sample from a donor that has granulocytes that do kill cancer cells (e.g. granulocytes that do kill at least 5% of cancer cells in a method described herein), in which case the method may be used to detect donors having granulocytes with optimal cancer killing activity. In one embodiment the control sample comprises granulocytes that kill up to 50%, 40%, 30%, 20% or 10% of cancer cells in a method described herein. Preferably the control sample comprises granulocytes that kill up to 5% of cancer cells in a method described herein. 
     Preferably a haematopoietic cell is obtained when the % of cancer cells killed in the test sample is at least 5% greater than the % of cancer cells killed in the control sample. In some embodiments the % of cancer cells killed in the test sample is at least 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70% or 80% greater than the % of cancer cells killed in the control sample. More preferably the % of cancer cells killed in the test sample is at least 35% greater than the % of cancer cells killed in the control sample. 
     In one embodiment the method comprises the use of a 5:1 ratio of granulocytes to cancer cells, and the haematopoietic cell is obtained when the % of cancer cells killed in the test sample is at least 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70% or 80% greater than the % of cancer cells killed in the control sample. More preferably the method comprises the use of a 5:1 ratio of granulocytes to cancer cells, and the haematopoietic cell is obtained when the % of cancer cells killed in the test sample is at least 30% greater than the % of cancer cells killed in the control sample. 
     In one embodiment the method comprises the use of a 10:1 ratio of granulocytes to cancer cells, and the haematopoietic cell is obtained when the % of cancer cells killed in the test sample is at least 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 70% or 80% greater than the % of cancer cells killed in the control sample. More preferably the method comprises the use of a 10:1 ratio of granulocytes to cancer cells, and the haematopoietic cell is obtained when the % of cancer cells killed in the test sample is at least 20% greater than the % of cancer cells killed in the control sample. 
     In one aspect the invention provides an in vitro method for obtaining a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. admixing a granulocyte obtainable from a donor with a cancer cell line to form an admixture;   b. incubating said admixture;   c. measuring the % of cancer cells killed in said test sample; and   d. obtaining a haematopoietic cell from a sample from said donor when said granulocyte kills at least 5% of the cancer cells in the test sample.       

     The haematopoietic cell may be obtained from a sample from said donor when the granulocyte kills at least 10%, 20%, 30%, 40%, or 50% of the cancer cells in the admixture. 
     In one embodiment a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 60% of the cancer cells in the admixture. 
     In one embodiment a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 70% of the cancer cells in the admixture. 
     Preferably a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 80% or 90% of the cancer cells in the admixture. 
     In one embodiment the method comprises the use of a 5:1 ratio of granulocytes to cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 30% of the cancer cells in the admixture. Preferably the method comprises the use of a 5:1 ratio of granulocytes to cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 40% of the cancer cells in the admixture. 
     In one embodiment the method comprises the use of a 10:1 ratio of granulocytes to cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 45%, 50% or 60% (preferably at least 60%) of the cancer cells in the admixture. More preferably the method comprises the use of a 10:1 ratio of granulocytes to cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 80% of the cancer cells in the admixture. 
     In some embodiments the cancer cell line is a cervical cancer cell line (e.g. HeLa). 
     In one embodiment the method comprises the use of a 5:1 ratio of granulocytes to cervical cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 30% of the cervical cancer cells in the admixture. Preferably the method comprises the use of a 5:1 ratio of granulocytes to cervical cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 40% of the cervical cancer cells in the admixture. 
     In one embodiment the method comprises the use of a 10:1 ratio of granulocytes to cervical cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 45%, 50% or 60% (preferably at least 60%) of the cervical cancer cells in the admixture. More preferably the method comprises the use of a 10:1 ratio of granulocytes to cervical cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 80% of the cervical cancer cells in the admixture. 
     In some embodiments the cancer cell line is a pancreatic cancer cell line (e.g. PANC-1). 
     In one embodiment the method comprises the use of a 5:1 ratio of granulocytes to pancreatic cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 50% or 60% of the pancreatic cancer cells in the admixture. Preferably the method comprises the use of a 5:1 ratio of granulocytes to pancreatic cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 65% or 70% of the pancreatic cancer cells in the admixture. 
     In one embodiment the method comprises the use of a 10:1 ratio of granulocytes to pancreatic cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 70% of the pancreatic cancer cells in the admixture. Preferably the method comprises the use of a 10:1 ratio of granulocytes to pancreatic cancer cells, and a haematopoietic cell is obtained from a sample from said donor when the granulocyte kills at least 80% or 90% of the pancreatic cancer cells in the admixture. 
     In one aspect there is provided an in vitro method for selecting a granulocyte that selectively kills a cancer cell, said method comprising:
         a. contacting a cancer cell line with a granulocyte obtainable from a donor to form a test sample, and incubating said test sample; and   b. selecting said granulocyte as selective for a cancer cell when the % of cancer cells killed in the test sample is greater than the % of non-cancer cells killed in a control sample, wherein the control sample comprises a non-cancer cell line and a granulocyte obtainable from the same donor.       

     The method preferably comprises a further step of obtaining a haematopoietic cell from a sample from said donor when the granulocyte is selected. 
     The % of non-cancer cells killed in a control sample may be determined either prior to carrying out the present method or at the same time as carrying out the present method (preferably at the same time). 
     For example, in one embodiment said method comprises:
         a. contacting a cancer cell line with a granulocyte obtainable from a donor to form a test sample;   b. contacting a non-cancer cell line with a granulocyte (e.g. control granulocyte) obtainable from the same donor to form a control sample;   c. incubating said samples; and   d. selecting said granulocyte as selective for a cancer cell when the % of cancer cells killed in the test sample is greater than the % of non-cancer cells killed in the control sample.       

     In some embodiments the method may comprise the use of a plurality of different test samples comprising granulocytes from further donors (e.g. second, third, fourth donors, etc.). 
     In one embodiment a granulocyte is considered selective for a cancer cell when the % of cancer cells killed in the test sample is at least 2%, 5%, 10%, 15%, 20%, 30%, 40% or 50% greater than the % of non-cancer cells in the test sample. 
     In one embodiment the method comprises the use of a 5:1 ratio of granulocytes to cancer cells, and the haematopoietic cell is obtained when the % of cancer cells killed in the test sample is at least 10%, 20% or 30% greater than the % of cancer cells killed in the control sample. 
     In one embodiment the method comprises the use of a 10:1 ratio of granulocytes to cancer cells, and the haematopoietic cell is obtained when the % of cancer cells killed in the test sample is at least 10% or 20% greater than the % of cancer cells killed in the control sample. 
     Preferably a granulocyte kills less than 35%, 25%, 15%, 10%, 5% or 1% of non-cancer cells in a method described herein. 
     Any non-cancer cell line may be used in the foregoing method. In one embodiment the non-cancer cell line is an epithelial cell, such as a mammary epithelial cell. Preferably the non-cancer cell line is a MCF-12F non-cancer cell line (commercially available from the American Type Culture Collection, 10801 University Boulevard. Manassas, Va. 20110 USA as ATCC® CRL-10783™). 
     In one embodiment there is provided a method for selecting a granulocyte that selectively kills a cancer cell, said method comprising:
         a. contacting a cancer cell line with a granulocyte obtainable from a donor to form a test sample, and incubating said test sample;   b. selecting said granulocyte when:
           i. the % of cancer cells killed in the test sample is greater than the % of cancer cells killed in a first control sample, wherein the first control sample comprises a cancer cell line of the same type and a granulocyte obtainable from a different donor; and   ii the % of cancer cells killed in the test sample is greater than the % of non-cancer cells killed in a second control sample, wherein the second control sample comprises a non-cancer cell line and a granulocyte (e.g. control granulocyte) obtainable from the same donor (as the donor in step a.).   
               

     In some embodiments a method may comprise comparing the % of non-cancer cells killed by two or more (cultures of) granulocytes from different donors, thus allowing selection of a granulocyte (and donor) which shows the lowest % killing of non-cancer cells. 
     In one aspect the invention provides an in vitro method for selecting a granulocyte suitable for use in treating pancreatic cancer, said method comprising:
         a. admixing a granulocyte with a pancreatic cancer cell line to form an admixture;   b. incubating said admixture;   c. measuring the % of pancreatic cancer cells killed in said admixture; and   d. selecting a granulocyte that kills at least 5% of the pancreatic cancer cells in the admixture.       

     The pancreatic cancer cell line may be a pancreatic ductal adenocarcinoma cell line. 
     The granulocyte may kill at least 10%, 20%, 30%, 40%, or 50 of the pancreatic cancer cells in the admixture. 
     In one embodiment said granulocyte kills at least 60% of the pancreatic cancer cells in the admixture. 
     In one embodiment said granulocyte kills at least 70% of the pancreatic cancer cells in the admixture. 
     Preferably said granulocyte kills at least 80% or 90% of the pancreatic cancer cells in the admixture. 
     In one embodiment the method comprises the use of a 5:1 ratio of granulocytes to pancreatic cancer cells, and the granulocyte kills at least 50% or 60% of the pancreatic cancer cells in the admixture. Preferably the method comprises the use of a 5:1 ratio of granulocytes to pancreatic cancer cells, and the granulocyte kills at least 65% or 70% of the pancreatic cancer cells in the admixture. 
     In one embodiment the method comprises the use of a 10:1 ratio of granulocytes to pancreatic cancer cells, and the granulocyte kills at least 70% of the pancreatic cancer cells in the admixture. Preferably the method comprises the use of a 10:1 ratio of granulocytes to pancreatic cancer cells, and the granulocyte kills at least 80% or 90% of the pancreatic cancer cells in the admixture. 
     In some embodiments the cancer cell line is a pancreatic cancer cell line (e.g. PANC-1). 
     A related aspect provides an in vitro method for selecting a granulocyte suitable for use in treating cancer, said method comprising:
         a. admixing a granulocyte with a plurality of different cancer cell lines to provide a plurality of admixtures;   b. incubating said admixtures;   c. measuring the % of cancer cells killed in said admixtures; and   d. selecting a granulocyte as suitable for use in treating a cancer of the same type/subset as the cancer cell line, when said granulocyte kills at least 5% of the cancer cells in the admixture.       

     Advantageously, such a method allows rapid screening of a granulocyte for the ability to kill multiple cancer types/subsets. In some embodiments the granulocyte is then catalogued according to the types/subsets of cancer that the granulocyte is suitable for use in treating. 
     The term “type” as used in this context means cancer of the same organ or tissue as the cancer cell line. For example, if the cancer cell line is a pancreatic ductal adenocarcinoma cell line, then a granulocyte that kills at least 5% of pancreatic ductal adenocarcinoma cells in an admixture is considered to be suitable for use in treating all pancreatic cancers. 
     The term “subset” as used in this context means not only that the cancer is of the same organ or tissue, but that the cancer shares additional characteristics with the cancer cell line (e.g. both are carcinomas, sarcomas, etc. of the same organ or tissue). For example if the cancer cell line is a pancreatic ductal adenocarcinoma cell line, then a granulocyte that kills at least 70% of pancreatic ductal adenocarcinoma cells in an admixture is considered to be suitable for use in treating all pancreatic ductal adenocarcinoma variants. 
     The foregoing in vitro methods may further comprise measuring and/or selecting a granulocyte based on a surface potential (e.g. cell surface charge) as disclosed herein. The foregoing in vitro methods may further comprise measuring and/or selecting a granulocyte based on cell density (e.g. of at least 1.077 g/ml) as disclosed herein. The foregoing in vitro methods may further comprise measuring and/or selecting a granulocyte based on the expression or activity of toll-like receptors; and/or an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2 on said granulocyte. 
     The in vitro methods according to the foregoing aspects may be representative of Cancer Killing Activity (CKA) assays (e.g. claim  6 ). 
     The term “admix” as used herein means mixing one or more components together in any order, whether sequentially or simultaneously. In one embodiment “admix” means contacting a first component with a second component (e.g. a granulocyte and a cancer cell line). 
     The term “plurality” means at least two. In one embodiment “plurality” means at least 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. “Plurality” may mean at least 30, 40, 50, 60, 70, 80, 90 or 100. In one embodiment “plurality” means 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. In another embodiment “plurality” means 30, 40, 50, 60, 70, 80, 90 or 100. 
     In one embodiment the granulocyte is obtainable from a donor, for example a human donor. Alternatively or additionally the granulocyte may be obtainable from a subject having a cancer of a different type/subset to the cancer cell line(s) used in a method of the invention. Advantageously, the inventors have found that a subject having cancer of one type/subset may have granulocytes with the ability to kill cancer cells of a different cancer type/subset. This is surprising, especially when the subject has particularly low concentrations of granulocytes with the ability to kill cells of the cancer with which the subject has been diagnosed. 
     The cancer cell line for use in a method of the present invention may be one or more selected from a pancreatic cancer cell line, a liver cancer cell line, an oesophageal cancer cell line, a stomach cancer cell line, a cervical cancer cell line, an ovarian cancer cell line, a lung cancer cell line, a bladder cancer cell line, a kidney cancer cell line, a brain cancer cell line, a prostate cancer cell line, a myeloma cancer cell line, a non-Hodgkin&#39;s lymphoma (NHL) cell line, a larynx cancer cell line, a uterine cancer cell line, or a breast cancer cell line. 
     Suitable cell lines are available commercially from the American Type Culture Collection United Kingdom (U.K.), Guernsey, Ireland, Jersey and Liechtenstein, LGC Standards, Queens Road, Teddington, Middlesex, TW11 0LY, UK. For example, a pancreatic cell line may be one or more of Capan-2, ATCC HTB-80; Panc 10.05, ATCC CRL-2547; CFPAC-1, ATCC CRL-1918; HPAF-II, ATCC CRL-1997; SW 1990, ATCC CRL-2172; BxPC-3, ATCC CRL-1687; AsPC-1, ATCC CRL-1682; ATCC® TCP-1026™; SW1990, ATCC CRL-2172; SU.86.86, ATCC CRL-1837; BXPC-3, ATCC CRL-1687; Panc 10.05, ATCC CRL-2547; MIA-PaCa-2, ATCC CRL-1420; PANC-1, ATCC CRL-1469; or ATCC® TCP-2060™. 
     Preferably the cancer cell line is pancreatic cancer cell line, such as PANC-1. 
     In one embodiment the cancer cell line is a cervical cancer cell line, such as a HeLa cell. 
     The incubation step may be carried out for between 1 hour and 100 hours. Suitably, the incubation step may be carried out for between 5 hours and 75 hours, for example between 10 hours and 20 hours. 
     The incubation step may be carried out for between 6 hours to 6 days. Suitably, the incubation step may be carried out for between 6 hours and 2 days, for example for between 12 hours to 36 hours, such as between 16 to 24 hours. In one embodiment the incubation step is carried out for 24 hours. The incubation step may be carried out at any temperature suitable for cell growth and viability, for example at a temperature between 35° C. to 42° C., suitably at 37 or 39° C. Preferably the incubation step is carried out at 37 or 39° C. for 24 hours. Preferably the incubation step is carried out for 16-24 hours at 30-40° C. (e.g. 37° C.). 
     The % of cancer cells killed can be measured by reference to the total number of starting cancer cells. The number of cancer cells killed can be measured using any suitable means, for example by viability staining (e.g. trypan blue staining), and microscopy, or using other automated means, for example by cell electronic sensing equipment, such as the RT-CES™ system available from ACEA Biosciences, Inc. (11585 Sorrento Valley Rd., Suite 103, San Diego, Calif. 92121, USA). In some embodiments the % of cancer cells killed may be determined within 24 hours (e.g. of incubating a cancer cell line and a granulocyte). The % of cancer cells killed is preferably the maximum number of cancer cells killed when carrying out a method of the invention. 
     The number of cancer cells killed can be also be measured using the ACEA Biosciences xCELLigence RTCA DP Analyzer System®. The xCELLigence System is a real-time cell analyser, allowing for label-free and dynamic monitoring of cellular phenotypic changes continuously by measuring electrical impedance. Such measurements may be carried out as detailed in Example 11. Said System is commercially available from ACEA Biosciences 6779 Mesa Ridge Road #100, San Diego, Calif. 92121 USA. 
     The methods of the present invention may comprise the use of at least a 1:1, 5:1 or 10:1 ratio of granulocytes to cancer cells. Preferably the methods comprise the use of a 5:1 ratio of granulocytes to cancer cells. More preferably the methods comprise the use of a 10:1 ratio of granulocytes to cancer cells. 
     The skilled person understands that where the methods of the invention comprise a comparison step between two samples (e.g. between a “test sample” and a “control sample”) that conditions (e.g. assay conditions during the method) should be kept consistent. For example, the concentration ratio of granulocytes to cancer cells should be the same, as should the time conditions, etc. Where a comparison is made between two samples herein, suitably the samples are equivalent. For example, the samples being compared may be the same sample types (e.g. blood) and subjected to the same processing steps. In some embodiments the only difference between samples is the donor from which said samples are obtained. For example, in embodiments where the proportion of cells having a particular property is being determined, the total number of cells in each sample may be the same so that a proper comparison can be made. 
     In one embodiment the admixture comprises 8×10 5  granulocytes and 1.5×10 4  cancer cells, or preferably 8×10 5  granulocytes and 8×10 4  cancer cells. 
     In one embodiment a granulocyte may kill at least 5% of cancer cells in a method described herein. A granulocyte may kill at least 10%, 20%, 30%, 40%, or 50% of the cancer cells in a method described herein. In one embodiment a granulocyte may kill at least 60% of the cancer cells in a method described herein. In one embodiment a granulocyte may kill at least 70% of the cancer cells in a method described herein. Preferably a granulocyte may kill at least 80% or 90% of the cancer cells in a method described herein. 
     In embodiments where the method comprises the use of a 5:1 ratio of granulocytes to cancer cells, a granulocyte may kill at least 30% of the cancer cells in a method described herein. Preferably where the method comprises the use of a 5:1 ratio of granulocytes to cancer cells, a granulocyte may kill at least 40% of the cancer cells in a method described herein. In embodiments where the method comprises the use of a 10:1 ratio of granulocytes to cancer cells, a granulocyte may kill at least 45%, 50% or 60% (preferably at least 60%) of the cancer cells in a method described herein. More preferably where the method comprises the use of a 10:1 ratio of granulocytes to cancer cells, a granulocyte may kill at least 80% of the cancer cells in a method described herein. 
     In some embodiments the cancer cell line is a cervical cancer cell line (e.g. HeLa). In embodiments where the method comprises the use of a 5:1 ratio of granulocytes to cervical cancer cells, a granulocyte may kill at least 30% of the cervical cancer cells in a method described herein. Preferably where the method comprises the use of a 5:1 ratio of granulocytes to cervical cancer cells, a granulocyte may kill at least 40% of the cervical cancer cells in a method described herein. In embodiments where the method comprises the use of a 10:1 ratio of granulocytes to cervical cancer cells, a granulocyte may kill at least 45%, 50% or 60% (preferably at least 60%) of the cervical cancer cells in a method described herein. More preferably where the method comprises the use of a 10:1 ratio of granulocytes to cervical cancer cells, a granulocyte may kill at least 80% of the cervical cancer cells in a method described herein. 
     In some embodiments the cancer cell line is a pancreatic cancer cell line (e.g. PANC-1). In embodiments where the method comprises the use of a 5:1 ratio of granulocytes to pancreatic cancer cells, a granulocyte may kill at least 50% or 60% of the pancreatic cancer cells in a method described herein. Preferably where the method comprises the use of a 5:1 ratio of granulocytes to pancreatic cancer cells, a granulocyte may kill at least 65% or 70% of the pancreatic cancer cells in a method described herein. In embodiments where the method comprises the use of a 10:1 ratio of granulocytes to pancreatic cancer cells, a granulocyte may kill at least 70% of the pancreatic cancer cells in a method described herein. Preferably where the method comprises the use of a 10:1 ratio of granulocytes to pancreatic cancer cells, a granulocyte may kill at least 80% or 90% of the pancreatic cancer cells in a method described herein. 
     Granulocytes that kill less than 5% of cancer cells are preferably discarded. 
     Suitably, a granulocyte may be selected if it kills at least 80%, 85%, 90% or 95% of the cancer cells. Granulocytes that kill less than 70% (suitably less than 80%, 85%, 90% or 95%) of the cancer cells are preferably discarded. 
     In one embodiment an in vitro method for selecting a granulocyte suitable for use in treating cancer comprises:
         a. admixing a granulocyte with a cancer cell line (preferably a pancreatic cancer cell line or a plurality of different cancer cell lines) to provide an admixture (or plurality of admixtures), wherein each admixture comprises 8×10 5  granulocytes, and 8×10 4  cancer cells;   b. incubating said admixture (or admixtures) at 39° C. for 24 hours;   c. measuring the % of cancer cells killed in said admixture (or admixtures); and   d. selecting a granulocyte as suitable for use in treating a cancer of the same type/subset as the cancer cell line, when said granulocyte kills at least 5% of the cancer cells in the admixture.       

     In one embodiment an in vitro method according to the foregoing aspects may also comprise parallel assaying of the granulocytes of a subject to be treated. 
     An in vitro method according to the present invention may further comprise obtaining a haematopoietic cell from a donor from whom the selected granulocyte is obtainable or has been obtained. Thus, the in vitro methods of the invention may also constitute methods for selecting a haematopoietic cell suitable for use in treating cancer. 
     In another embodiment an in vitro method for selecting a haematopoietic cell suitable for use in treating cancer comprises:
         a. admixing a granulocyte obtainable from a donor with a plurality of different cancer cell lines to provide a plurality of admixtures;   b. incubating said admixtures;   c. measuring the % of cancer cells killed in said admixtures; and   d. selecting a haematopoietic cell from said donor as suitable for use in treating a cancer of the same type/subset as the cancer cell line killed by said granulocyte when said granulocyte kills at least 5% of the cancer cells in the admixture.       

     The in vitro method may further comprise measuring and/or selecting a haematopoietic cell based on a surface potential as disclosed herein and/or based on a surface potential of a granulocyte differentiated therefrom. The in vitro method may further comprise measuring and/or selecting a haematopoietic cell based on cell density (e.g. of at least 1.077 g/ml) as disclosed herein and/or based on a cell density (e.g. of at least 1.077 g/ml) of a granulocyte differentiated therefrom. The in vitro method may further comprise measuring and/or selecting a haematopoietic cell based on the expression or activity of toll-like receptors; and/or an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2 on a granulocyte differentiated therefrom. 
     In one aspect there is provided a haematopoietic cell obtainable (e.g. obtained) by a method of the present invention. 
     In one aspect there is provided a granulocyte obtainable (e.g. obtained) by a method of the invention. 
     Haematopoietic cells selected in accordance with the present invention can be differentiated into granulocytes (e.g. neutrophils) having advantageous properties. For example said granulocytes may kill cancer cells more rapidly than granulocytes obtained directly from a donor. In one embodiment granulocytes obtained from haematopoietic cells described herein have a half-maximal cancer kill % within 15 hours of contacting cancer cells. Preferably, said granulocytes obtained from haematopoietic cells described herein have a half-maximal cancer kill % within 10 hours of contacting cancer cells. 
     Suitably, such values are obtained when the ratio of granulocytes to cancer cells used in a method described herein is 10:1. 
     The term “half-maximal cancer kill %” as used in this context means half of the total cancer cells capable of being killed by a granulocyte. For example, if a granulocyte kills 50% of total cancer cells used in a method described herein, then the half-maximal cancer kill % will be 25% of the total cancer cells used in the assay. 
     In some embodiments, granulocytes that kill less than 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60% or 65% of cancer cells may be discarded. 
     The in vitro methods of the invention may comprise a combination of the techniques described herein to improve selection of cells suitable for treating cancer. For example, if multiple haematopoietic cells or granulocytes are selected because they meet the stipulated density threshold, cell surface potential/electrophoretic mobility may be assessed to help identify haematopoietic cells that produce high CKA granulocytes (e.g. neutrophils) or to select those granulocytes having improved CKA. Advantageously such a combination of techniques improves the ability to select haematopoietic cells or granulocytes of the invention. Moreover, by applying a combination of such techniques on granulocytes (e.g. neutrophils), cells with improved CKA may be detected, and haematopoietic cells obtained from said donors. 
     The invention also provides a differentiation method, said method comprising differentiating an in vitro cell culture of haematopoietic cells of the invention, or haematopoietic cells obtainable according to a method of the invention into granulocytes. In a related aspect there is provided an in vitro cell culture of granulocytes obtainable (e.g. obtained) by such a method. In one embodiment the in vitro cell culture is enriched with granulocytes having:
         a. a surface potential defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec (or at least 1.0 μm·cm/volt·sec, for example at least 1.25 μm·cm/volt·sec, 1.5 μm·cm/volt·sec, or 1.75 μm·cm/volt·sec); and   b. the ability to kill cancer cells.       

     In one aspect the invention provides a pharmaceutical composition comprising: a haematopoietic cell; and a granulocyte-macrophage colony-stimulating factor (GM-CSF), a granulocyte colony-stimulating factor (G-CSF), a growth hormone; serotonin, vitamin C, vitamin D, glutamine (Gln), arachidonic acid, AGE-albumin, an interleukin, TNF-alpha, Flt-3 ligand, thrombopoietin, foetal bovine serum (FBS), or combinations thereof. 
     In one embodiment a pharmaceutical composition comprises a haematopoietic cell; and a granulocyte-macrophage colony-stimulating factor (GM-CSF), and a granulocyte colony-stimulating factor (G-CSF), and a growth hormone, and serotonin, and vitamin C, and vitamin D, and glutamine (Gln), and arachidonic acid, and AGE-albumin, and an interleukin, and TNF-alpha, and Flt-3 ligand, and thrombopoietin, and foetal bovine serum (FBS). 
     Suitably a growth hormone may be a human growth hormone. The haematopoietic cell comprised in the composition may be obtainable (e.g. obtained) by a method of the present invention, or may be part of an in vitro cell culture of haematopoietic cells of the invention. 
     In one aspect the invention provides a pharmaceutical composition comprising: a granulocyte cell; a granulocyte-macrophage colony-stimulating factor (GM-CSF), a granulocyte colony-stimulating factor (G-CSF), a growth hormone; serotonin, vitamin C, vitamin D, glutamine (Gln), arachidonic acid, AGE-albumin, an interleukin, TNF-alpha (e.g. UniProt accession number P01375), Flt-3 ligand, thrombopoietin (e.g. UniProt accession number P40225), foetal bovine serum (FBS), or combinations thereof. The granulocyte cell comprised in the composition may be obtainable (e.g. obtained) by a method of the present invention. 
     In one embodiment a pharmaceutical composition comprises a granulocyte cell; and a granulocyte-macrophage colony-stimulating factor (GM-CSF), and a granulocyte colony-stimulating factor (G-CSF), and a growth hormone, and serotonin, and vitamin C, and vitamin D, and glutamine (Gln), and arachidonic acid, and AGE-albumin, and an interleukin, and TNF-alpha, and Flt-3 ligand, and thrombopoietin, and foetal bovine serum (FBS). 
     An interleukin may be interleukin-3 (IL-3) (e.g. UniProt accession number P08700), interleukin 8 (IL-8) (e.g. UniProt accession number P10145), Interleukin-4 (IL-4) (e.g. UniProt accession number P05112), Interleukin-6 (IL-6) (e.g. UniProt accession number P05231), interleukin-18 (IL-18) (e.g. UniProt accession number Q14116), or combinations thereof. Suitably an interleukin may be interleukin-3 (IL-3), interleukin 8 (IL-8), Interleukin-4 (IL-4), Interleukin-6 (IL-6), and interleukin-18 (IL-18). 
     In one embodiment a granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), growth hormone, serotonin, AGE-albumin, interleukin, TNF-alpha, Flt-3 ligand, or thrombopoietin may be a human granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), growth hormone, serotonin, AGE-albumin, interleukin, TNF-alpha, Flt-3 ligand, or thrombopoietin. 
     All of the above reagents are commercially available from Sino Biological Inc. (Suite B-310 (also Suite B-209, B-203), 14 Zhong He Street, BDA, Beijing 100176, P.R.China). 
     The invention also relates to a haematopoietic cell, an in vitro cell culture of haematopoietic cells, a granulocyte, an in vitro cell culture of granulocytes, a pharmaceutical composition or a kit described herein for use as a medicament. The medicament may be for use in treating cancer, thus in a related aspect there is provided a haematopoietic cell, an in vitro cell culture of haematopoietic cells, a granulocyte, an in vitro cell culture of granulocytes, a pharmaceutical composition or a kit for use in treating cancer. A corresponding method for treating cancer is also provided comprising administering to a subject in need thereof an in vitro cell culture of haematopoietic cells, a granulocyte, an in vitro cell culture of granulocytes, a pharmaceutical composition or a kit of the invention. 
     In another aspect the invention provides a cell bank comprising a haematopoietic cell, an in vitro cell culture of haematopoietic cells, a granulocyte, an in vitro cell culture of granulocytes, or a pharmaceutical composition of the invention. 
     In a further aspect there is provided a kit comprising:
         a. an in vitro cell culture of haematopoietic cells, a haematopoietic cell, a granulocyte, an in vitro cell culture of granulocytes, or a pharmaceutical composition of the invention; and   b. instructions for use of same in medicine.       

     The term “haematopoietic cell” as used herein refers to a cell that is capable of differentiating into a granulocyte (preferably a neutrophil). The term “haematopoietic cell” thus encompasses a haematopoietic stem cell, as well as a precursor cell (e.g. differentiated from a haematopoietic stem cell), wherein said precursor cell is capable of differentiating into a granulocyte (preferably a neutrophil). The precursor cell may be referred to herein as a “granulocyte precursor cell”. A haematopoietic cell in accordance with the present invention may relate to a haematopoietic stem cell, a granulocyte precursor cell or combinations thereof. Preferably the term “haematopoietic cell” as used herein does not encompass a human embryonic stem cell. In one embodiment, a haematopoietic cell is a cell of the haematopoiesis pathway or a cell equivalent thereto. In one embodiment, the haematopoietic cell is an induced pluripotent stem cell (iPSC) or a cell equivalent thereto. In one embodiment, an iPSC is obtainable from a somatic cell of a donor. Generation of iPSCs is a well-known technique in the art, see Yu et al (2007), Science, 318:1917-1920 the teaching of which is incorporated herein by reference. 
     In one embodiment, a haematopoietic cell is a nuclear transfer embryonic stem cell (NT-ESC) or equivalent thereto. In one embodiment, an NT-ESC is obtainable by injecting the nucleus of a cell from the donor into an egg cell from which the original nucleus has been removed. Generation of NT-ESCs is a well-known technique in the art, see Tachibana M, Amato P, Sparman M, et al (2013), Cell, 154(2): 465-466 the teaching of which is incorporated herein by reference. 
     In one embodiment where a haematopoietic cell is obtained from a sample from a donor, said haematopoietic cell may be isolated from said sample. In another embodiment where a haematopoietic cell is obtained from a sample from a donor, said sample is a sample comprising somatic cells and the haematopoietic cell is obtained by inducing pluripotency of a cell (e.g. a somatic cell) in said sample to obtain an iPSC. 
     In another embodiment where a haematopoietic cell is obtained from a sample from a donor, said sample is a sample comprising somatic cells and the haematopoietic cell is obtained by injecting the nucleus of a cell (e.g. a somatic cell) in said sample into an egg cell (e.g. from which the original nucleus has been removed) to obtain an NT-ESC. 
     In one embodiment a haematopoietic cell is a haematopoietic stem cell. A haematopoietic stem cell can be selected on the basis of cell surface polypeptide markers, for example selected from CD34 (e.g. UniProt accession number P28906), CD59 (e.g. UniProt accession number P13987), Thy1 (e.g. UniProt accession number P04216), CD38 (e.g. UniProt accession number P28907), C-kit (e.g. UniProt accession number P10721), and lin. In one embodiment a haematopoietic stem cell comprises the cell surface polypeptide markers CD34 + , CD59 + , Thy1 + , CD38 low/− , C-kit low/− , and lin − . Preferably a haematopoietic cell expresses CD34. Antibodies to detect the presence or absence of said markers are commercially available and may be obtained from BD Biosciences Europe, ebioscience, Beckman Coulter and Pharmingen, for example. 
     In another embodiment a haematopoietic cell is a granulocyte precursor cell. A granulocyte precursor cell may be one or more selected from a common myeloid progenitor cell, a myeloblast, a N. promyelocyte, a N. myelocyte, a N. metamyelocyte, a N. band, or combinations thereof. 
     A haematopoietic cell (such as a haematopoietic stem cell or a granulocyte precursor cell) or cell culture may be differentiated into a granulocyte. Differentiation may be carried out using any suitable method, such as a method based on the disclosure in Lieber et al, Blood, 2004 Feb. 1; 103(3):852-9, and/or Choi et al, Nat. Protoc., 2011 March; 6(3):296-313, and/or Timmins et. al. Biotechnology and bioengineering. 2009; 104(4):832-40, which are incorporated herein by reference. 
     In one aspect the invention provides a method of differentiating a haematopoietic cell comprising admixing said haematopoietic cell with a granulocyte-macrophage colony-stimulating factor (GM-CSF), a granulocyte colony-stimulating factor (G-CSF), a growth hormone; serotonin, vitamin C, vitamin D, glutamine (Gln), arachidonic acid, AGE-albumin, an interleukin, TNF-alpha, Flt-3 ligand, thrombopoietin, foetal bovine serum (FBS), or combinations thereof. 
     In one embodiment the invention provides a method of differentiating a haematopoietic cell comprising admixing said haematopoietic cell with a granulocyte-macrophage colony-stimulating factor (GM-CSF), and a granulocyte colony-stimulating factor (G-CSF), and a growth hormone, and serotonin, and vitamin C, and vitamin D, and glutamine (Gln), and arachidonic acid, and AGE-albumin, and an interleukin, and TNF-alpha, and Flt-3 ligand, and thrombopoietin, and foetal bovine serum (FBS). 
     Said haematopoietic cell may be part of a haematopoietic cell culture. 
     In one embodiment differentiation of a haematopoietic cell comprises culturing said haematopoietic cell with one or more feeder cell(s). Suitably, a feeder cell may be an OP9 cell. OP9 cells (ATCC® CRL-2749™) are commercially available from the American Type Culture Collection United Kingdom (U.K.), Guernsey, Ireland, Jersey and Liechtenstein, LGC Standards, Queens Road, Teddington, Middlesex, TW11 0LY, UK. In one embodiment a haematopoietic cell may be cultured with one or more feeder cell(s) and Flt-3 ligand, thrombopoietin, fetal bovine serum (FBS), or combinations thereof. 
     Thus in one embodiment, a pharmaceutical composition or cell culture of the invention may further comprise a feeder cell, such as an OP9 cell. 
     The term “granulocyte” encompasses the following cell types: neutrophils, basophils, and eosinophils. Preferably the granulocyte is a neutrophil. A granulocyte may express the cell surface polypeptide markers CD11 b (e.g. UniProt accession number P11215) and CD15. A granulocyte may also produce reactive oxygen species (O 2   − ). 
     The present invention encompasses granulocytes that are suitable for use in treating cancer. Suitably, said granulocytes comprise a surface potential defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec (suitably at least 2.25 μm·cm/volt·sec or at least 2.5 μm·cm/volt·sec). In one embodiment said granulocytes comprise a surface potential defined by an electrophoretic mobility of at least 2.75 μm·cm/volt·sec, or at least 3.0 μm·cm/volt·sec. Suitably, said granulocytes may comprise a surface potential defined by an electrophoretic mobility of at least 3.25 μm·cm/volt·sec, or at least 3.5 μm·cm/volt·sec. Preferably said granulocytes may comprise a surface potential defined by an electrophoretic mobility of at least 3.75 μm·cm/volt·sec, or at least 4.0 μm·cm/volt·sec). The granulocytes also have the ability to kill cancer cells. 
     Alternatively, said granulocytes may comprise a surface potential defined by an electrophoretic mobility of at least 1.0 μm·cm/volt·sec or at least 1.25 μm·cm/volt·sec. For example, said granulocytes may comprise a surface potential defined by an electrophoretic mobility of at least 1.5 μm·cm/volt·sec, or at least 1.75 μm·cm/volt·sec. The granulocytes also have the ability to kill cancer cells. 
     The “ability to kill cancer cells” can be determined by admixing a cell (e.g. a granulocyte, such as a neutrophil) with a cancer cell, and measuring (e.g. after incubation) viability of said cancer cell. If the cancer cell is no longer viable (i.e. has been killed), the cell exhibits an ability to kill cancer cells. In one embodiment the ability to kill cancer cells is determined using a Cancer Killing Activity (CKA) assay described herein. 
     In one embodiment a CKA assay comprises:
         a. contacting a cancer cell line with a granulocyte to form a test sample (preferably at a ratio of 10:1 granulocytes to cancer cells);   b. incubating said test sample; and   c. measuring the % of cancer cells killed in said test sample.       

     In one embodiment a CKA assay comprises:
         a. admixing a granulocyte with a cancer cell line to provide an admixture (preferably at a ratio of 10:1 granulocytes to cancer cells);   b. incubating said admixture; and   c. measuring the % of cancer cells killed in said admixture       

     In a preferable embodiment a CKA assay comprises:
         a. admixing a granulocyte with a cancer cell line to provide an admixture, wherein said admixture comprises 8×10 5  granulocytes, and 8×10 4  cancer cells;   b. incubating said admixture at 39° C. for 24 hours;   c. measuring the % of cancer cells killed in said admixture.       

     In a preferable embodiment a CKA assay comprises:
         a. admixing a granulocyte with a cancer cell line to provide an admixture, wherein said admixture comprises at least 1:1 (e.g. 5:1 or 10:1) granulocytes to cancer cells;   b. incubating said admixture for 16-24 hours (e.g. at 30-40° C.);   c. measuring the % of cancer cells killed in said admixture.       

     In one embodiment a granulocyte may be considered to kill cancer cells if it kills at least 5% of cancer cells in a method described herein. A granulocyte may be considered to kill cancer cells if it kills at least 10%, 20%, 30%, 40%, or 50% of the cancer cells present. In one embodiment a granulocyte may be considered to kill cancer cells if it kills at least 60% of the cancer cells present. In one embodiment a granulocyte may be considered to kill cancer cells if it kills at least 70% of the cancer cells present. Preferably a granulocyte may be considered to kill cancer cells if it kills at least 80% or 90% of the cancer cells present. 
     In embodiments where the method comprises the use of a 5:1 ratio of granulocytes to cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 30% of the cancer cells present. Preferably where the method comprises the use of a 5:1 ratio of granulocytes to cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 40% of the cancer cells present. In embodiments where the method comprises the use of a 10:1 ratio of granulocytes to cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 45%, 50% or 60% (preferably at least 60%) of the cancer cells present. More preferably where the method comprises the use of a 10:1 ratio of granulocytes to cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 80% of the cancer cells present. 
     In some embodiments the cancer cell line is a cervical cancer cell line (e.g. HeLa). In embodiments where the method comprises the use of a 5:1 ratio of granulocytes to cervical cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 30% of the cervical cancer cells present. Preferably where the method comprises the use of a 5:1 ratio of granulocytes to cervical cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 40% of the cervical cancer cells present. In embodiments where the method comprises the use of a 10:1 ratio of granulocytes to cervical cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 45%, 50% or 60% (preferably at least 60%) of the cervical cancer cells present. More preferably where the method comprises the use of a 10:1 ratio of granulocytes to cervical cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 80% of the cervical cancer cells present. 
     In some embodiments the cancer cell line is a pancreatic cancer cell line (e.g. PANC-1). In embodiments where the method comprises the use of a 5:1 ratio of granulocytes to pancreatic cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 50% or 60% of the pancreatic cancer cells present. Preferably where the method comprises the use of a 5:1 ratio of granulocytes to pancreatic cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 65% or 70% of the pancreatic cancer cells present. In embodiments where the method comprises the use of a 10:1 ratio of granulocytes to pancreatic cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 70% of the pancreatic cancer cells present. Preferably where the method comprises the use of a 10:1 ratio of granulocytes to pancreatic cancer cells, a granulocyte may be considered to kill cancer cells if it kills at least 80% or 90% of the pancreatic cancer cells present. 
     Granulocytes that kill less than 5% of cancer cells are preferably discarded. 
     The foregoing paragraphs apply to each of the methods described herein, and said disclosures may be combined with any of the methods described herein. 
     A cell with the ability to kill cancer cells (“considered to kill cancer cells”) may be defined as a cell that has at least 70% or 75% CKA in a CKA assay herein (e.g. a CKA assay above). Suitably, said cell may have at least 80% or 90% activity in a CKA assay herein (e.g. a CKA assay above). 
     A cell with the “ability to kill cancer cells” (“considered to kill cancer cells”) is suitable for use in treating cancer. Haematopoietic cells that can be differentiated into cells with the “ability to kill cancer cells” are also considered to be suitable for use in treating cancer. 
     In one aspect the invention provides an in vitro cell culture of haematopoietic cells, wherein said haematopoietic cells differentiate to form granulocytes characterised by:
         a. a density of at least 1.077 g/ml; and   b. the ability to kill cancer cells.       

     In one aspect the invention provides an in vitro cell culture of haematopoietic cells, wherein said haematopoietic cells differentiate to form granulocytes characterised by:
         a. a density of greater than 1.077 g/ml; and   b. the ability to kill cancer cells.       

     A granulocyte having a density of at least 1.077 g/ml may be obtainable by a method described in Example 21. In one embodiment such a method comprises:
         i. providing a sucrose solution adjusted to a density of 1.077 g/ml;   ii. adding a composition comprising granulocytes; and   iii. centrifuging to pellet high-density granulocytes (e.g. neutrophils).       

     A granulocyte having a density of at least 1.077 g/ml may be obtainable using a commercially available kit, such as the Histopaque®-1077 kit (commercially available from Sigma-Aldrich, Catalogue No. 10771-100M L). 
     In some embodiments a granulocyte having a density of 1.077 g/ml is obtained by Ficoll-Paque separation. Typically such granulocytes are found in the bottom of a 1.077 Ficoll-Paque medium following separation, while lower density granulocytes (e.g. having a density of less than 1.077 g/ml) are found at the 1.077-plasma interface. 
     Thus, a granulocyte according to (and for use in) the present invention may have a density of at least 1.077 g/ml, and granulocytes having a density of less than 1.077 g/ml may be excluded from the present invention. In some embodiments, a granulocyte according to the invention has a density of at least 1.077 g/ml and a cell surface potential described herein. Therefore, all of the cell surface potential embodiments apply equally to said granulocytes. 
     Preferably the granulocyte has a density greater than 1.077 g/ml. 
     In one embodiment a granulocyte has a density of at least 1.078 g/ml. In one embodiment a granulocyte has a density of at least 1.079 g/ml. In one embodiment a granulocyte has a density of at least 1.080 g/ml. In one embodiment a granulocyte has a density of at least 1.081 g/ml. In one embodiment a granulocyte has a density of at least 1.082 g/ml. In one embodiment a granulocyte has a density of at least 1.083 g/ml. Preferably the granulocyte has a density of 1.082 g/ml or more than 1.082 g/ml. 
     In one embodiment a granulocyte has a density of less than 1.084 g/ml. In one embodiment a granulocyte has a density of less than 1.083 g/ml. In one embodiment a granulocyte has a density of less than 1.082 g/ml. In one embodiment a granulocyte has a density of less than 1.081 g/ml. In one embodiment a granulocyte has a density of less than 1.080 g/ml. In one embodiment a granulocyte has a density of less than 1.079 g/ml. In one embodiment a granulocyte has a density of less than 1.078 g/ml. 
     In one embodiment a granulocyte has a density of 1.077 g/ml to 1.084 g/ml (e.g. a density greater than 1.077 g/ml but less than 1.084 g/ml). The granulocyte may have a density of 1.079 g/ml to 1.084 g/ml, for example a density of 1.080 g/ml to 1.084 g/ml. The granulocyte may have a density of 1.080 g/ml to 1.083 g/ml, for example a density of 1.080 g/ml to 1.082 g/ml. 
     In one embodiment a haematopoietic cell has a density of at least 1.077 g/ml. Preferably the haematopoietic cell has a density greater than 1.077 g/ml. 
     In one embodiment a haematopoietic cell has a density of at least 1.078 g/ml. In one embodiment a haematopoietic cell has a density of at least 1.079 g/ml. In one embodiment a haematopoietic cell has a density of at least 1.080 g/ml. In one embodiment a haematopoietic cell has a density of at least 1.081 g/ml. In one embodiment a haematopoietic cell has a density of at least 1.082 g/ml. In one embodiment a haematopoietic cell has a density of at least 1.083 g/ml. 
     In one embodiment a haematopoietic cell has a density of less than 1.084 g/ml. In one embodiment a haematopoietic cell has a density of less than 1.083 g/ml. In one embodiment a haematopoietic cell has a density of less than 1.082 g/ml. In one embodiment a haematopoietic cell has a density of less than 1.081 g/ml. In one embodiment a haematopoietic cell has a density of less than 1.080 g/ml. In one embodiment a haematopoietic cell has a density of less than 1.079 g/ml. In one embodiment a haematopoietic cell has a density of less than 1.078 g/ml. 
     In one embodiment a haematopoietic cell has a density of 1.077 g/ml to 1.084 g/ml (e.g. a density greater than 1.077 g/ml but less than 1.084 g/ml). The haematopoietic cell may have a density of 1.079 g/ml to 1.084 g/ml, for example a density of 1.080 g/ml to 1.084 g/ml. The haematopoietic cell may have a density of 1.080 g/ml to 1.083 g/ml, for example a density of 1.080 g/ml to 1.082 g/ml. 
     In one aspect the invention provides a method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. measuring the density of a granulocyte cell obtainable from a donor; and   b. selecting a haematopoietic cell from said donor when the measured density of the granulocyte is at least 1.077 g/ml.       

     The invention also provides a method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. measuring the density of a haematopoietic cell; and   b. selecting a haematopoietic cell that has a density greater than an otherwise identical haematopoietic cell that differentiates to form a granulocyte having a density of less than 1.077 g/ml and/or has a reduced ability to kill cancer cells       

     In one aspect there is provided a method comprising differentiating an in vitro cell culture of haematopoietic cells, wherein said haematopoietic cells differentiate to form granulocytes characterised by:
         a. a density of at least 1.077 g/ml; and   b. the ability to kill cancer cells.       

     The invention also provides an in vitro culture of granulocytes obtainable by the foregoing method. 
     In one aspect the invention provides an in vitro cell culture of haematopoietic cells, wherein said haematopoietic cells differentiate to form granulocytes characterised by:
         a. expression or activity of toll-like receptors; and/or an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2; and   b. the ability to kill cancer cells.       

     The presence or absence of said receptors may be determined using any techniques known to the person skilled in the art. For example, the skilled person may use a labelled antibody optionally in combination with FACS to detect the presence or absence of said receptors. 
     Receptor activity/inactivity may also be determined using any known technique. For example, by detecting changes in gene expression associated with said activity/inactivity. 
     Preferably the granulocytes express toll-like receptors; and do not express programmed death 1 (PD-1) receptor (e.g. UniProt accession number Q15116); CD115 (e.g. UniProt accession number P07333); CD224 (e.g. UniProt accession number P19440); CXCR1 (e.g. UniProt accession number P25024); and/or CXCR2 (e.g. UniProt accession number P25025) (preferably do not express programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and CXCR2). 
     Alternatively or additionally, one or more of the PD-1 receptor; CD115; CD224; CXCR1; and CXCR2 may be expressed in an inactive form, or inactivated subsequent to expression. 
     The toll-like receptor may be one or more of: TLR1 (e.g. UniProt accession number Q15399), TLR2 (e.g. UniProt accession number 060603), TLR3 (e.g. UniProt accession number 015455), TLR4 (e.g. UniProt accession number 000206), TLR5 (e.g. UniProt accession number 060602), TLR6 (e.g. UniProt accession number Q9Y2C9), TLR7 (e.g. UniProt accession number Q9NYK1), TLR8 (e.g. UniProt accession number Q9NR97), TLR9 (e.g. UniProt accession number Q9NR96), TLR10 (e.g. UniProt accession number Q9BXR5), and/or TLR11 (e.g. UniProt accession number Q6R590). Preferably the toll-like receptor is TLR4. 
     Without wishing to be bound by theory, the inventors believe that:
         PD-L1 does not engage with its receptor PD-1 on granulocytes (e.g. neutrophils) with high CKA and/or that granulocytes (e.g. neutrophils) with high CKA do not produce PD-L1; and/or   granulocytes (e.g. neutrophils) with high CKA have active toll-like receptors on their surface; and/or   CD115 and CD224 markers are not expressed on granulocytes (e.g. neutrophils) with high CKA;   CXCR1 and CXCR2 are receptors of granulocytes (e.g. neutrophils) with low CKA, i.e. granulocytes (e.g. neutrophils) with high CKA do not express CXCR1 &amp; CXCR2, or CXCR1 and CXCR2 are inhibited in said granulocytes (e.g. neutrophils).       

     In one embodiment granulocytes having a cell surface polypeptide expression profile described above also have a cell surface potential and/or a density described herein. 
     In one aspect the invention provides a method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. detecting the expression or activity of toll-like receptors; programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2 on a granulocyte cell obtainable from a donor; and   b. selecting a haematopoietic cell from said donor when the toll-like receptors are expressed or activity; and/or programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2 are not expressed or inactive.       

     In one aspect there is provided a method comprising differentiating an in vitro cell culture of haematopoietic cells, wherein said haematopoietic cells differentiate to form granulocytes characterised by:
         a. expression or activity of toll-like receptors; and/or an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2; and   b. the ability to kill cancer cells.       

     The invention also provides an in vitro culture of granulocytes obtainable by the foregoing method. 
     A haematopoietic cell may be immortalised. The person skilled in the art is familiar with immortalisation techniques, which include inter alia introduction of a viral gene that deregulates the cell cycle (e.g. the adenovirus type 5 E1 gene), and artificial expression of telomerase. Immortalisation advantageously allows for the preparation of a cell line which can be stably cultured in vitro. Thus, in one aspect the invention provides an immortalised cell line obtainable (e.g. obtained) from a selected haematopoietic cell, as well as a stable haematopoietic cell culture. Suitably an immortalised cell line or stable haematopoietic cell culture is obtainable (e.g. obtained) by a method of the present invention. 
     The term “stable” as used in reference to a haematopoietic cell culture or cell line means that the cell culture or cell line has been modified such that it is more amenable to in vitro cell culture than an unmodified cell (i.e. a cell obtained from a donor and subjected directly to in vitro cell culture). Said “stable” cell culture or cell line is therefore capable of undergoing more rounds of replication (preferably for prolonged periods of time) when compared to an unmodified cell. 
     A haematopoietic cell is suitably obtainable (e.g. obtained) from a donor, for example a human donor. 
     The term “donor” as used herein refers to a subject (suitably a human subject) from whom a biofluid sample is obtained. Any suitable biofluid sample from which a haematopoietic cell or granulocyte cell is obtainable may be used in the present invention. 
     Thus, the term “sample” as used herein in reference to a sample from a donor may be any sample comprising a haematopoietic cell or from which a haematopoietic cell is obtainable (e.g. where said haematopoietic cell is an iPSC said sample may comprise a somatic cell). 
     In one embodiment a biofluid sample (or “sample”) is a blood sample, such as a peripheral blood sample. The term “blood” as used herein encompasses whole blood, blood serum, and blood plasma. Blood may be subjected to centrifugation in order to separate red blood cells, white blood cells, and plasma. Following centrifugation, the mononuclear cell layer may be removed for use in the present invention. 
     The donor may be selected based on one or more of the following characteristics: sex, age, medical history, and/or blood group type. In one embodiment a donor may be selected if said donor is a male. In another embodiment a donor may be selected if said donor is aged 18-25 (suitably 18-24). Suitably, a donor may be selected if said donor is a male aged between 18-25 (suitably 18-24). Without wishing to be bound by theory, it is believed that males in early adulthood have a higher likelihood of producing granulocytes (e.g. neutrophils) having the ability to kill cancer cells. 
     Suitably granulocytes obtainable (e.g. obtained) from a donor may have a surface potential defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec, and the ability to kill cancer cells. In another embodiment granulocytes obtainable (e.g. obtained) from a donor have a surface potential defined by an electrophoretic mobility of at least 1.0 μm·cm/volt·sec, and the ability to kill cancer cells. 
     The present invention also relates to the measurement of cell surface potentials. A surface potential of a cell can be determined using any suitable technique known in the art. In one embodiment the surface potential is determined using electrophoresis. The electrophoresis technique may be carried out by applying a voltage to cells comprised within a suitable electrophoresis medium, and measuring cell mobility. The following protocol may be employed:
         i. apply 200V direct current to cells (suspended in 10 mM Tris-HCl and 291 mM glucose buffer) comprised in an electrophoresis chamber; and   ii. measure the time taken for said cells (e.g. granulocytes or haematopoietic cells) to pass a fixed length while applying a current of 3 mA (e.g. via use of a microscope, optionally connected to a CCD camera).       

     Electrophoretic mobility “μ” (expressed in units μm·cm/volt·sec) can be calculated using the following formula: 
       μ= ugS/I  
 
     wherein:
         “u”=the electrophoretic velocity measured by step ii.;   “g”=the conductivity of the electrophoresis medium;   “S”=the cross-sectional area of the electrophoresis chamber; and   “l”=the current.       

     In one embodiment electrophoretic mobility is determined by:
         i. adding haematopoietic cells or granulocytes suspended in 10 mM Tris-HCl and 291 mM glucose to an electrophoresis chamber;   ii. applying 200V/3 mA direct current; and   iii. measuring the distance (mm) said haematopoietic cells or granulocytes travel in a given time towards the electrode; and   iv. calculating the electrophoretic mobility using the equation above.       

     The electrophoresis may be carried out in a 0.9% (isotonic) NaCl solution. Preferably a constant current is used (e.g. 3 mA). 
     An electrophoretic mobility assay may be one described in “Cell Electrophoresis” edited by Johann Bauer (ISBN 0-8493-8918-6 published by CRC Press, Inc.) the teaching of which is incorporated herein in its entirety. 
     Without wishing to be bound by theory, it is believed that haematopoietic cells (e.g. haematopoietic stem cells expressing CD34) that can differentiate into granulocytes (e.g. neutrophils) with higher CKA, are more positively charged and therefore travel further towards the negatively charged electrode in a given time than similar size and weight/density haematopoietic cells (e.g. haematopoietic stem cells expressing CD34) that differentiate into lower CKA granulocytes (e.g. neutrophils). Likewise, it is believed that granulocytes (e.g. neutrophils) with higher CKA, are more positively charged and therefore travel further towards the negatively charged electrode in a given time than similar size and weight/density granulocytes (e.g. neutrophils) that may have lower CKA. 
     Preferably the cell surface potential is equivalent to the electrophoretic mobility, and is proportional to the distance travelled by the cell in a given time during electrophoresis. A cell with a higher positive charge travels further towards the electrode during electrophoresis than a less positively-charged (or negatively-charged) cell. Such a cell will therefore have a greater cell surface potential value than a less positively-charged (or negatively-charged) cell. The surface potential of a cell may be defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec or at least 2.25 μm·cm/volt·sec. Suitably the surface potential of a cell may be defined by an electrophoretic mobility of at least 2.5 μm·cm/volt·sec or at least 2.75 μm·cm/volt·sec. Suitably the surface potential of a cell may be defined by an electrophoretic mobility of at least 3.0 μm·cm/volt·sec or at least 3.25 μm·cm/volt·sec. Preferably the surface potential of a cell may be defined by an electrophoretic mobility of at least 3.5 μm·cm/volt·sec or at least 3.75 μm·cm/volt·sec. More preferably the surface potential of a cell may be defined by an electrophoretic mobility of at least 4.0 μm·cm/volt·sec. The cell may be a haematopoietic cell, or a granulocyte cell. 
     In one embodiment a haematopoietic cell of the invention may have a surface potential defined by an electrophoretic mobility of at least 1.0 μm·cm/volt·sec or at least 1.25 μm·cm/volt·sec, for example at least 1.5 μm·cm/volt·sec or 1.75 μm·cm/volt·sec (preferably at least 2.0 μm·cm/volt·sec). In one embodiment, a haematopoietic cell may have a surface potential defined by an electrophoretic mobility of at least 2.25 μm·cm/volt·sec or at least 2.5 μm·cm/volt·sec. Suitably, a haematopoietic cell may have a surface potential defined by an electrophoretic mobility of at least 2.75 μm·cm/volt·sec or at least 3.0 μm·cm/volt·sec. Preferably, a haematopoietic cell may have a surface potential defined by an electrophoretic mobility of at least 3.25 μm·cm/volt·sec or at least 3.5 μm·cm/volt·sec. More preferably, a haematopoietic cell may have a surface potential defined by an electrophoretic mobility of at least 3.75 μm·cm/volt·sec or at least 4.0 μm·cm/volt·sec. 
     In one embodiment a granulocyte cell of the invention may have a surface potential defined by an electrophoretic mobility of at least 1.0 μm·cm/volt·sec or at least 1.25 μm·cm/volt·sec, for example at least 1.5 μm·cm/volt·sec or at least 1.75 μm·cm/volt·sec (preferably at least 2.0 μm·cm/volt·sec). In one embodiment, a granulocyte cell may have a surface potential defined by an electrophoretic mobility of at least 2.25 μm·cm/volt·sec or at least 2.5 μm·cm/volt·sec. Suitably, a granulocyte cell may have a surface potential defined by an electrophoretic mobility of at least 2.75 μm·cm/volt·sec or at least 3.0 μm·cm/volt·sec. Preferably, a granulocyte cell may have a surface potential defined by an electrophoretic mobility of at least 3.25 μm·cm/volt·sec or at least 3.5 μm·cm/volt·sec. More preferably, a granulocyte cell may have a surface potential defined by an electrophoretic mobility of at least 3.75 μm·cm/volt·sec or at least 4.0 μm·cm/volt·sec. 
     The present invention may comprise measuring the surface potential of granulocytes obtainable (e.g. obtained) from a donor. If the surface potential is defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec (or alternatively at least 1.0 μm·cm/volt·sec), haematopoietic cells are selected from the donor. Advantageously, this provides a simple and/or quick and/or reliable screening method for the selection of haematopoietic cells suitable for use in treating cancer. In some embodiments by the employed method constitutes a quick screen can be used to determine if a donor is suitable, without the need for a more complex assay (such as a CKA assay). A functional assay (such as a CKA assay described herein) may be subsequently performed to validate the screening, for example by differentiating haematopoietic cells selected from a donor into granulocytes, and testing said granulocytes in a CKA assay. Cells that do not have the required cell surface potential and/or required CKA may be discarded. 
     Additionally or alternatively, a surface potential of a haematopoietic cell may be measured, and a haematopoietic cell selected if it has a greater surface potential than an otherwise identical haematopoietic cell that differentiates to form a granulocyte (e.g. a neutrophil) having a surface potential defined by an electrophoretic mobility of less than 2.0 μm·cm/volt·sec (preferably less than 2.5 μm·cm/volt·sec, more preferably less than 3.5 μm·cm/volt·sec or 4.0 μm·cm/volt·sec); and/or which has a reduced ability to kill cancer cells. Advantageously, this allows the rapid screening of haematopoietic cells to determine whether said cells are suitable for use in treating cancer. Thus, the invention encompasses haematopoietic cells having a greater surface potential than an otherwise identical haematopoietic cell that differentiates to form a granulocyte (e.g. a neutrophil) having a surface potential defined by an electrophoretic mobility of less than 2.0 μm·cm/volt·sec ((preferably less than 2.5 μm·cm/volt·sec, more preferably less than 3.5 μm·cm/volt·sec or 4.0 μm·cm/volt·sec); and/or which has a reduced ability to kill cancer cells. 
     In one embodiment haematopoietic cells that do not meet the screening criteria (e.g. that do not have a greater surface potential and/or which have a surface potential defined by an electrophoretic mobility of less than 2.0 μm·cm/volt·sec) are discarded. 
     Additionally or alternatively, a surface potential of a haematopoietic cell may be measured, and a haematopoietic cell selected if it has a greater surface potential than an otherwise identical haematopoietic cell that differentiates to form a granulocyte (e.g. a neutrophil) having a surface potential defined by an electrophoretic mobility of less than 1.0 μm·cm/volt·sec (suitably less than 1.25 μm·cm/volt·sec, more suitably less than 1.5 μm·cm/volt·sec or 1.75 μm·cm/volt·sec); and/or which has a reduced ability to kill cancer cells. Thus, the invention encompasses haematopoietic cells having a greater surface potential than an otherwise identical haematopoietic cell that differentiates to form a granulocyte (e.g. a neutrophil) having a surface potential defined by an electrophoretic mobility of less than 1.0 μm·cm/volt·sec (suitably less than 1.25 μm·cm/volt·sec, more suitably less than 1.5 μm·cm/volt·sec or 1.75 μm·cm/volt·sec); and/or which has a reduced ability to kill cancer cells. 
     In one embodiment haematopoietic cells that do not meet the screening criteria (e.g. that do not have a greater surface potential and/or which have a surface potential defined by an electrophoretic mobility of less than 1.0 μm·cm/volt·sec) are discarded. 
     The term “greater surface potential” means a more positive surface charge. 
     The “reduced ability to kill cancer cells” can be determined experimentally, by testing two or more granulocytes (e.g. neutrophils) under the same experimental conditions, and comparing the concentration/amount of cancer cells killed. The “reduced ability to kill cancer cells” may be determined using a method or CKA assay described herein. In one embodiment a “reduced ability to kill cancer cells” means that a cell kills 10% or 20% fewer cancer cells than cells of the invention (i.e. cells having the “ability to kill cancer cells” as defined herein). Preferably a “reduced ability to kill cancer cells” means that a cell kills less 5% or fewer cancer cells than cells of the invention. 
     Thus, following this method an appropriate haematopoietic cell surface potential value (allowing selection of haematopoietic cells that can be differentiated into granulocytes suitable for use in treating cancer) can be determined empirically, based on the correlation between the surface potential of granulocytes obtainable therefrom, and/or based on the ability to kill cancer cells. 
     In a related aspect the invention provides a method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. measuring a surface potential of a haematopoietic cell obtainable from a donor, wherein a granulocyte (e.g. a neutrophil) obtainable from said donor is characterised by:
           i. a surface potential defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec (or at least 1.0 μm·cm/volt·sec); and   ii. the ability kill cancer cells; and   
           b. using the measured surface potential in a method for selecting a haematopoietic cell.       

     The “method for selecting a haematopoietic cell” may refer to selecting a haematopoietic cell from the same donor from which the surface potential measurement has been obtained, or from a different donor. 
     In one aspect the invention provides an in vitro method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. measuring the cell surface charge of a granulocyte obtainable from a donor; and   b. obtaining a haematopoietic cell from a sample from said donor when said granulocyte has a more positive cell surface charge when compared to a control granulocyte.       

     The control granulocyte may have a negative, positive or neutral charge. Preferably the control granulocyte has a positive charge. Preferably a control granulocyte is a granulocyte that does not kill cancer cells (e.g. does not kill at least 5% of cancer cells in a method described herein). The control granulocyte is preferably obtained from a different donor to the donor of step a. 
     In one embodiment the method comprises obtaining a haematopoietic cell from a sample from said donor when said granulocyte has a cell surface charge that is at least 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or 300% more positively charged when compared to a control granulocyte. 
     In another aspect the invention provides an in vitro method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. measuring the cell surface charge of a haematopoietic cell obtainable from a donor; and   b. selecting said haematopoietic cell as suitable for use in treating cancer when said haematopoietic cell has a more positive cell surface charge when compared to a control haematopoietic cell.       

     The cell surface charge of the control granulocyte or haematopoietic cell may be determined either prior to carrying out the present method or at the same time as carrying out the present method (preferably at the same time). 
     For example, in one embodiment said method comprises:
         a. measuring the cell surface charge of a granulocyte or haematopoietic cell obtainable from a donor;   b. measuring the cell surface charge of a control granulocyte or haematopoietic cell; and   c. obtaining a haematopoietic cell from a sample from said donor when said granulocyte has a more positive cell surface charge when compared to said control granulocyte; or selecting said haematopoietic cell as suitable for use in treating cancer when said haematopoietic cell has a more positive cell surface charge when compared to a control haematopoietic cell.       

     In some embodiments the method may comprise the use of a plurality of different test samples comprising granulocytes from further donors (e.g. second, third, fourth donors, etc.). 
     The control haematopoietic cell may have a negative, positive or neutral charge. Preferably the control haematopoietic cell has a positive charge. Preferably a control haematopoietic cell is a haematopoietic cell that does not differentiate into a granulocyte that kills cancer cells (e.g. said haematopoietic cell does not differentiate into a granulocyte that kills at least 5% of cancer cells in a method described herein). The control haematopoietic cell is preferably obtained from a different donor to the donor of step a. 
     In one embodiment the method comprises obtaining a haematopoietic cell from a sample from said donor when said haematopoietic cell has a cell surface charge that is at least 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or 300% more positively charged when compared to a control haematopoietic cell. 
     In one aspect there is provided an in vitro method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. measuring the concentration of granulocytes having a positive cell surface charge in a sample obtainable from a donor; and   b. obtaining a haematopoietic cell from a sample from said donor when the concentration of said granulocytes having a positive cell surface charge is greater than the concentration of granulocytes having a positive cell surface charge in an otherwise identical control sample from a different donor.       

     The control sample referred to may be a sample from a donor that has granulocytes that do not kill cancer cells (e.g. granulocytes that do not kill at least 5% of cancer cells in a method described herein). 
     In one embodiment the method comprises obtaining a haematopoietic cell from a sample from said donor when the concentration of granulocytes having a positive cell surface charge is at least 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or 300% greater than the concentration of granulocytes having a positive cell surface charge in an otherwise identical control sample from a different donor. Preferably when the concentration of granulocytes having a positive cell surface charge is at least 50% greater than the concentration of granulocytes having a positive cell surface charge in an otherwise identical control sample from a different donor. 
     In another aspect there is provided an in vitro method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. measuring the concentration of haematopoietic cells having a positive cell surface charge in a sample obtainable from a donor; and   b. selecting a haematopoietic cell as suitable for use in treating cancer when the concentration of said haematopoietic cells having a positive cell surface charge is greater than the concentration of haematopoietic cells having a positive cell surface charge in an otherwise identical control sample from a different donor.       

     The concentration of granulocytes or haematopoietic cells having a positive cell surface charge in an otherwise identical control sample from a different donor may be determined either prior to carrying out the present method or at the same time as carrying out the present method (preferably at the same time). 
     For example, in one embodiment said method comprises:
         a. measuring the concentration of granulocytes or haematopoietic cells having a positive cell surface charge in a sample obtainable from a (first) donor;   b. measuring the concentration of granulocytes or haematopoietic cells having a positive cell surface charge in an otherwise identical control sample from a different donor; and   c. obtaining a haematopoietic cell from a sample from said (first) donor when the concentration of said granulocytes having a positive cell surface charge is greater than the concentration of granulocytes having a positive cell surface charge in the otherwise identical control sample; or selecting a haematopoietic cell as suitable for use in treating cancer when the concentration of said haematopoietic cells having a positive cell surface charge from said (first) donor is greater than the concentration of haematopoietic cells having a positive cell surface charge in an otherwise identical control sample.       

     In some embodiments the method may comprise the use of a plurality of different test samples comprising granulocytes from further donors (e.g. second, third, fourth donors, etc.). 
     The control sample referred to may be a sample from a donor that has haematopoietic cells that do not differentiate into granulocytes that kill cancer cells (e.g. said haematopoietic cells do not differentiate into granulocytes that kill at least 5% of cancer cells in a method described herein). 
     In one embodiment the method comprises obtaining a haematopoietic cell from a sample from said donor when the concentration of haematopoietic cells having a positive cell surface charge is at least 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or 300% greater than the concentration of haematopoietic cells having a positive cell surface charge in an otherwise identical control sample from a different donor. Preferably when the concentration of haematopoietic cells having a positive cell surface charge is at least 50% greater than the concentration of haematopoietic cells having a positive cell surface charge in an otherwise identical control sample from a different donor. 
     In one aspect there is provided an in vitro method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. measuring the cell surface charge of a granulocyte obtainable from a first donor;   b. identifying a granulocyte obtainable from said first donor having a more positive cell surface charge when compared to a control granulocyte;   c. measuring the concentration of granulocytes identified in step b.;   d. comparing the concentration of said granulocytes measured in step c. with the concentration of granulocytes obtainable from a second (or further) donor, wherein the granulocytes from said second (or further) donor have a more positive cell surface charge when compared to the control granulocyte; and   e. obtaining a haematopoietic cell from a sample from said first donor when the comparison identifies a greater concentration of said granulocytes obtainable from said first donor when compared to the concentration of said granulocytes obtainable from said second (or further) donor.       

     In one embodiment the granulocytes obtainable from the first donor and those obtainable from the second donor being compared in step d. have an equivalent cell surface charge. 
     The control granulocyte may have a negative, positive or neutral charge. Preferably the control granulocyte has a positive charge. Preferably a control granulocyte is a granulocyte that does not kill cancer cells (e.g. does not kill at least 5% of cancer cells in a method described herein). The control granulocyte is preferably obtained from a different donor to the donor of step a. 
     In one embodiment the granulocyte obtainable from said first donor has a cell surface charge that is at least 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or 300% more positively charged when compared to a control granulocyte. 
     In one embodiment the comparison identifies a concentration of said granulocytes obtainable from said first donor that is at least 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or 300% greater than the concentration of said granulocytes obtainable from said second (or further) donor. Preferably at least 50% greater. 
     In one aspect there is provided an in vitro method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
         a. measuring the cell surface charge of a haematopoietic cell obtainable from a first donor;   b. identifying a haematopoietic cell obtainable from said first donor having a more positive cell surface charge when compared to a control haematopoietic cell;   c. measuring the concentration of haematopoietic cells identified in step b.;   d. comparing the concentration of said haematopoietic cells measured in step c. with the concentration of haematopoietic cells obtainable from a second (or further) donor, wherein the haematopoietic cells from said second (or further) donor have a more positive cell surface charge when compared to the control haematopoietic cell; and   e. selecting a haematopoietic cell obtainable from said first donor as suitable for use in treating cancer when the comparison identifies a greater concentration of said haematopoietic cells obtainable from said first donor when compared to the concentration of said haematopoietic cells obtainable from said second (or further) donor.       

     In one embodiment the haematopoietic cells obtainable from the first donor and those obtainable from the second donor being compared in step d. have an equivalent cell surface charge. 
     The cell surface charge of the control granulocyte or haematopoietic cell may be determined either prior to carrying out the present method or at the same time as carrying out the present method (preferably at the same time). 
     The control haematopoietic cell may have a negative, positive or neutral charge. Preferably the control haematopoietic cell has a positive charge. Preferably a control haematopoietic cell is a haematopoietic cell that does not differentiate into a granulocyte that kills cancer cells (e.g. said haematopoietic cell does not differentiate into a granulocyte that kills at least 5% of cancer cells in a method described herein). The control haematopoietic cell is preferably obtained from a different donor to the donor of step a. 
     In one embodiment the haematopoietic cell obtainable from said first donor has a cell surface charge that is at least 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or 300% more positively charged when compared to a control haematopoietic cell. 
     In one embodiment the comparison identifies a concentration of said haematopoietic cells obtainable from said first donor that is at least 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or 300% greater than the concentration of said haematopoietic cells obtainable from said second (or further) donor. Preferably at least 50% greater. 
     In some embodiments a further donor may be a third, fourth, fifth or sixth donor. 
     In one embodiment, measuring a cell surface charge comprises contacting a granulocyte or haematopoietic cell with a positively charged means and a negatively charged means (e.g. nanoparticle), wherein preferential binding of the granulocyte or haematopoietic cell to the positively charged means indicates that the cell surface is negatively charged, and wherein preferential binding of the granulocyte or haematopoietic cell to the negatively charged means indicates that the cell surface is positively charged. 
     In one embodiment, a granulocyte or haematopoietic cell has a positive cell surface charge when it can be bound by a negatively charged means, and not a positively charged means. In one embodiment, a granulocyte or haematopoietic cell has a negative cell surface charge when it can be bound by a positively charged means, and not a negatively charged means. 
     Such negatively and/or positively charged means may also be used to measure the concentration of a granulocyte or haematopoietic cell in a sample. 
     A positively charged means may be a positively charged particle, nanoprobe or nanoparticle, or a cation exchange media. 
     In one aspect the present invention involves isolating granulocytes or haematopoietic cells comprising a (more) positive cell surface charge by way of said charge. For example, said cells may be isolated using a negatively charged means, such as a negatively charged particle, nanoprobe or nanoparticle, or an anion exchange media. Such techniques may be used to measure the cell surface charge of granulocytes or the concentration of granulocytes having a positive cell surface charge in the foregoing embodiments. 
     The cells may be isolated from negatively charged, neutrally charged, or less positively charged granulocytes or haematopoietic cells. 
     In one embodiment, a positively or negatively charged means (e.g. nanoparticle) may be detectable by fluorescence. In another embodiment, a positively or negatively charged means (e.g. nanoparticle) may be capable of being captured by way of magnetism, thus allowing isolation of a cell that interacts with said means. 
     Suitable nanoparticles may be prepared by conjugating superparamagnetic Iron(II,III) oxide (Fe 3 O 4 ) nanoparticles (NPs) with (3-Aminopropyl)triethoxysilane (APTES) to form a thin layer of Silicon dioxide (SiO 2 ) shell on the NPs&#39; surface upon reaction with Tetraethyl orthosilicate (TEOS) and ammonium hydroxide (NH 4 OH). Fluorescein isothiocyanates (FITCs) may be embedded in the SiO 2  shell, thus exposing the Si-linked hydroxyl groups (SiO 2 —OH) and creating the negative surface charge. Branched poly(ethylene imine) (PEI) molecules may be used to not only to cover the SiO 2 —OH groups in a non-covalently manner but also to expose the additional amine groups that carry the positive charges. 
     Thus, in one embodiment a negatively charged nanoparticle is prepared by conjugating Fe 3 O 4  nanoparticles with APTES to form a thin layer of SiO 2  shell on the nanoparticle surface upon reaction with Tetraethyl orthosilicate (TEOS) and ammonium hydroxide (NH 4 OH), and embedding a FITC in the SiO 2  shell, thus exposing the SiO 2 —OH groups (creating the negative surface charge). 
     In another embodiment, a positively charged nanoparticle is prepared by contacting a negatively charged nanoparticle (as described herein) with a PEI molecule (e.g. to expose additional amine groups that carry a positive charge). 
     In one embodiment, the negatively charged means (e.g. nanoparticle) may have a negative surface charge of at least −5 mV, −10 mV, −20 mV, −30 mV, or −40 mV. Preferably, the negatively charged means (e.g. nanoparticle) has may have a negative surface charge of at least −35 mV. 
     In one embodiment, the positively charged means (e.g. nanoparticle) may have a positive surface charge of at least +5 mV, +10 mV, +20 mV, +30 mV, or +40 mV. Preferably, the positively charged means (e.g. nanoparticle) has may have a positive surface charge of at least +35 mV. 
     The surface charge of said positively or negatively charged means (e.g. nanoparticle) may refer to the surface zeta potential of the positively or negatively charged means (e.g. nanoparticle). The surface zeta potential may be measured with a Dynamic light scattering particle size analyser (e.g. the Zetasizer Nano-ZS90, Malvern, UK). 
     It is surprising that cell surface charge can be used to select granulocytes (having high cancer killing activity) and associated haematopoietic cells. For 60 years it has been maintained that all mammalian cells are negatively charged, and that this is consistent for the same cell type between individuals. Without wishing to be bound by theory, the present inventors believe that the currently-accepted theory that granulocytes are positive has arisen from a limitation of the techniques used to analyse cell surface charge (e.g. with soluble ions like Na+, Ca+ etc. being lost). The present inventors believe that the positive charge on the granulocytes may be provided by human neutrophil peptides (HNPs), which are the most abundant proteins in human neutrophils. HNPs contain 20-40 amino acids rich in arginine, lysine, and cysteine resulting the peptides to be positively-charged and called “cation peptides”. HNPs have an amphipathic folded rod-like structure with one side being hydrophobic and the other side being hydrophilic and positively charged. It is believed that the primary targets of HNPs are the negatively-charged lipid bilayer membranes on cancer cells. The activation mechanism of HNPs is the cleavage of negatively charged leader peptides that neutralize the positive charges in the peptide precursor. On target cells, the mature amphipathic HNPs exert two major effector actions. First, HNPs form barrel-like pores on plasma membranes of target cells. The hydrophobic side of the monomeric HNP lines up against the hydrophobic portion of the target bilayer membranes whereas the hydrophilic side of the HNP forms a hydrophilic pore with other similarly lined-up HNPs. The holes cause swelling and rupture (cytolysis) of target cancer cells. Second, HNPs, once they enter the cytoplasm of target cells that contain mitochondria, can bind to and neutralize the negatively-charged outer mitochondrial membranes, leading to dissipation of the mitochondrial transmembrane potential, a well-known mechanism for triggering rapid apoptosis. The present inventors therefore believe that granulocytes (e.g. neutrophils) with a more positive cell charge contain more HNPs and so have higher cancer killing activity. 
     In one embodiment the granulocytes obtained by a foregoing method may be functionally assayed by a cancer killing assay or method described herein. 
     A cell described herein may be part of a cell culture (e.g. an in vitro cell culture). The cell culture may comprise multiple different cell types (e.g. apart from the haematopoietic cell, or granulocyte cell). 
     In one embodiment the cell culture is an in vitro cell culture of haematopoietic cells. The cell culture may be enriched with haematopoietic cells that differentiate to form granulocytes characterised by a surface potential defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec (or at least 1.0 μm·cm/volt·sec); and the ability to kill cancer cells. Alternatively or additionally, the cell culture may be enriched with haematopoietic cells that differentiate to form granulocytes having: a density of at least 1.077 g/ml; and the ability to kill cancer cells. Alternatively or additionally, the cell culture may be enriched with haematopoietic cells that differentiate to form granulocytes having expression or activity of toll-like receptors; and/or an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2; and the ability to kill cancer cells. 
     In one embodiment the term “enriched with haematopoietic cells” means that the haematopoietic cells described herein (e.g. selected by the present methods) constitute at least 70%, 75%, 80%, 85%, 90% or 95% of the total haematopoietic cells (preferably total cells) comprised in the cell culture. 
     In one embodiment the term “enriched with haematopoietic cells” means that haematopoietic cells that differentiate to form granulocytes characterised by:
         (i) a surface potential defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec (or at least 1.0 μm·cm/volt·sec); or   (ii) a density of at least 1.077 g/ml; or   (iii) expression or activity of toll-like receptors; and/or an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2; and
 
the ability to kill cancer cells, constitute at least 70%, 75%, 80%, 85%, 90% or 95% of the total haematopoietic cells (preferably total cells) comprised in the cell culture.
       

     In another embodiment the cell culture is an in vitro cell culture of granulocytes. Said granulocytes are obtainable by differentiating a haematopoietic cell of the invention. The in vitro cell culture of granulocytes may be enriched with granulocytes having a surface potential defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec (or at least 1.0 μm·cm/volt·sec); and the ability to kill cancer cells. Alternatively or additionally, the cell culture may be enriched with granulocytes having: a density of at least 1.077 g/ml; and the ability to kill cancer cells. Alternatively or additionally, the cell culture may be enriched with granulocytes having expression or activity of toll-like receptors; and/or an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2; and the ability to kill cancer cells. 
     In one embodiment the term “enriched with granulocytes” means that the granulocytes described herein (e.g. selected by the present methods) constitute at least 70%, 75%, 80%, 85%, 90% or 95% of the total granulocytes (preferably total cells) comprised in the cell culture. 
     In one embodiment the term “enriched with granulocytes” means that granulocytes having:
         (i) a surface potential defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec (or at least 1.0 μm·cm/volt·sec); or   (ii) a density of at least 1.077 g/ml; or   (iii) expression or activity of toll-like receptors; and/or an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2; and
 
the ability to kill cancer cells, constitute at least 70%, 75%, 80%, 85%, 90% or 95% of the total granulocytes (preferably total cells) comprised in the cell culture.
       

     A cell, cell culture or pharmaceutical composition of the invention may be subjected to one or more further processing steps, such as cryogenic freezing. The further processing step may include admixing said cell, cell culture or pharmaceutical composition with a preservation medium, for example a cryogenic preservation medium. 
     The invention may further comprise depositing a cell, cell culture, or pharmaceutical composition of the invention in a cell bank, and thus in a related aspect provides a cell bank comprising a cell, cell culture or pharmaceutical composition. The term “cell bank” as used herein refers to a storage facility which maintains a cell under suitable conditions for cell viability. For example, the cell may be stored in a metabolically dormant state (e.g. cryogenically frozen). Suitably, a cell comprised within a cell bank is catalogued for appropriate retrieval (e.g. based on blood group, and/or human leukocyte antigen (HLA) type). In one embodiment a cell may be catalogued based on the type of cancer it (or a cell differentiated therefrom) kills. Where the cell bank is a granulocyte cell bank, said cell bank may be replenished using a haematopoietic cell of the invention. In some embodiments a haematopoietic cell or granulocyte obtained from a donor may be stored and later administered to said donor (e.g. if said donor is diagnosed with cancer), thus constituting a personalised medicine. 
     A cell or cell culture of the invention may be formulated in any suitable manner, based on its downstream application (e.g. storage in a cell bank, or use in therapy). 
     Thus, one aspect of the invention provides a cell bank comprising an in vitro cell culture of the haematopoietic cell or in vitro cell culture thereof, granulocyte or in vitro cell culture thereof, or pharmaceutical composition of the present invention. 
     In one embodiment a cell or cell culture of the invention is formulated as a pharmaceutical composition comprising a cell or cell culture of the invention, and a granulocyte-macrophage colony-stimulating factor (GM-CSF), a granulocyte colony-stimulating factor (G-CSF), a growth hormone; serotonin, vitamin C, vitamin D, glutamine (Gln), arachidonic acid, AGE-albumin, an interleukin, TNF-alpha, Flt-3 ligand, thrombopoietin, foetal bovine serum (FBS), or combinations thereof. 
     In one embodiment the cell or cell culture of the invention is formulated as a pharmaceutical composition comprising a cell or cell culture of the invention, and a granulocyte-macrophage colony-stimulating factor (GM-CSF), and a granulocyte colony-stimulating factor (G-CSF), and a growth hormone, and serotonin, and vitamin C, and vitamin D, and glutamine (Gln), and arachidonic acid, and AGE-albumin, and an interleukin, and TNF-alpha, and Flt-3 ligand, and thrombopoietin, and foetal bovine serum (FBS). 
     In one embodiment a cell, cell culture or pharmaceutical composition is formulated with a pharmaceutically acceptable carrier. The term “pharmaceutically acceptable carrier” as used herein means a carrier that can be administered to a subject (e.g. a patient) intravenously, intra-arterially, intraperitoneally, intra-tumourally, intrathecally or combinations thereof (preferably intravenously) without causing harm to said subject. Thus in one embodiment a pharmaceutically acceptable carrier is an injectable carrier, such as a sterile physiological saline solution. 
     The present invention provides cells, cell cultures, pharmaceutical compositions, and kits for use in medicine. For example, there is provided a haematopoietic cell, an in vitro cell culture of haematopoietic cells, a granulocyte, an in vitro cell culture of granulocytes, a pharmaceutical composition or a kit of the invention for use as a medicament. The medicament is particularly useful in the treatment of cancer. 
     In one embodiment a cancer is a solid tumour cancer. The term “solid tumour cancer” refers to an abnormal, malignant mass of tissue that does not contain cysts or liquid inclusions. Examples of solid tumour cancers include carcinomas, sarcomas, and lymphomas. 
     A solid tumour cancer may be a carcinoma. A carcinoma may be selected from one or more of an adenocarcinoma, a basal cell carcinoma, a squamous cell carcinoma, an adenosquamous carcinoma, a renal cell carcinoma, a ductal carcinoma in situ (DCIS), an invasive ductal carcinoma, an anaplastic carcinoma, a large cell carcinoma, a small cell carcinoma or combinations thereof. A carcinoma may also be selected from epithelial neoplasms, squamous cell neoplasms, squamous cell carcinoma, basal cell neoplasms, basal cell carcinoma, transitional cell carcinomas, adenocarcinomas (such as Adenocarcinoma not otherwise specified (NOS), linitis plastica, vipoma, cholangiocarcinoma, hepatocellular carcinoma NOS, adenoid cystic carcinoma, renal cell carcinoma, Grawitz tumour), adnexal and skin appendage neoplasms, mucoepidermoid neoplasms, cystic mucinous and serous neoplasms, ductal lobular and medullary neoplasms, acinar cell neoplasms, or complex epithelial neoplasms. 
     Alternatively a solid tumour cancer may be a sarcoma. A sarcoma may be selected from Askin&#39;s tumour, sarcoma botryoides, chondrosarcoma, Ewing&#39;s, malignant hemangioendothelioma, malignant schwannoma, osteosarcoma, or soft tissue sarcomas (including alveolar soft part sarcoma, angiosarcoma, cystosarcoma phyllodes, dermatofibrosarcoma protuberans (DFSP), desmoid tumour, desmoplastic small round cell tumour, epithelioid sarcoma, extraskeletal chondrosarcoma, extraskeletal osteosarcoma, fibrosarcoma, gastrointestinal stromal tumour (GIST), hemangiopericytoma, hemangiosarcoma, Kaposi&#39;s sarcoma, leiomyosarcoma, liposarcoma, lymphangiosarcoma, malignant fibrous histiocytoma, undifferentiated pleomorphic sarcoma, malignant peripheral nerve sheath tumour (MPNST), neurofibrosarcoma, rhabdomyosarcoma, and synovial sarcoma). 
     Alternatively a solid tumour may be a lymphoma, such as a B-cell lymphoma, a T-cell lymphoma, a NK-cell lymphoma, or a Hodgkin&#39;s lymphoma. 
     In one embodiment an in vitro cell culture of haematopoietic cells, a haematopoietic cell, an in vitro cell culture of granulocytes, a granulocyte, a pharmaceutical composition or a kit of the invention is for use in treating one or more of: pancreatic cancer, liver cancer, oesophageal cancer, stomach cancer, cervical cancer, ovarian cancer, lung cancer, bladder cancer, kidney cancer, brain cancer, prostate cancer, myeloma cancer, non-Hodgkin&#39;s lymphoma (NHL), larynx cancer, uterine cancer, or breast cancer. 
     Preferably an in vitro cell culture of haematopoietic cells, a haematopoietic cell, an in vitro cell culture of granulocytes, a granulocyte, a pharmaceutical composition or a kit of the invention is for use in treating pancreatic cancer. The pancreatic cancer may be a pancreatic solid tumour cancer, such as a pancreatic adenocarcinoma (e.g. a pancreatic ductal adenocarcinoma). 
     The reference to “cancer cell” herein (e.g. in the context of the “ability to kill cancer cells”) may refer to a cancer cell of any of above-mentioned cancers. Suitably the “cancer cell” may be a solid tumour cancer cell, such as a pancreatic cancer cell. 
     In one aspect, the present invention provides a method of treating cancer, said method comprising:
         a. obtaining a granulocyte or haematopoietic cell by a method described herein; and   b. administering said granulocyte or haematopoietic cell to a subject.       

     In some embodiments the haematopoietic cell may be differentiated into a granulocyte prior to administration. 
     In one embodiment an in vitro cell culture of haematopoietic cells, a haematopoietic cell, an in vitro cell culture of granulocytes, a granulocyte, a pharmaceutical composition or a kit of the invention is administered to a subject (e.g. a subject with cancer). Prior to administration there may be a matching step between the medicament (e.g. comprising an in vitro cell culture of haematopoietic cells, an in vitro cell culture of granulocytes, or a pharmaceutical composition of the invention) and the subject to be treated. Matching may be based on data derived from the donor from which the haematopoietic cell, or granulocyte is derived, and similar data obtained from the subject to be treated. Matching may be achieved on the basis of blood group type, human leukocyte antigen (HLA) type similarity, or combinations thereof. 
     A typical treatment regimen may include administering from 10 6 , 10 7 , 10 8  or 10 9  cells to a subject, or up to 10 12 , 10 13  or 10 14  cells to a subject. In one embodiment a treatment regimen includes administering a dose of at least 1×10 9  cells to a subject. Suitably, a treatment regimen may include administering a dose of at least 2×10 9  cells or at least 5×10 9  cells to a subject. In one embodiment a treatment regimen may include administering a dose of at least 1×10 10  cells or at least 5×10 10  cells to a subject. At least 1×10 11  or at least 2×10 11  cells may be administered to a subject. In some embodiments between 1×10 9  to 3×10 11  or 1×10 10  to 3×10 11  cells are administered to a subject. Suitably, between 5×10 10  to 2.5×10 11  cells are administered to a subject. 
     A subject for treatment may be dosed once, twice, three times, four times, five times, or six times per week. Alternatively a subject may be dosed daily (e.g. once or twice daily). In other embodiments a subject may be dosed once weekly or bi-weekly. Preferably the dose is weekly. The skilled person will appreciate that the dose can be tailored based on the needs of the subject, and efficacy of the medicament. For example, where the medicament is highly efficacious, the dose may be lowered. 
     In one embodiment a subject for treatment is dosed weekly (e.g. once weekly) with at least 2×10 9  cells or at least 2×10 10  cells. Suitably, a subject for treatment may be dosed weekly with at least 1×10 11  or at least 2×10 11  cells. 
     The treatment term can be varied based on the response of the subject to the treatment, and/or the type and/or severity of the cancer. For example, the subject for treatment may be dosed for at least 1 or 2 weeks. Suitably the subject for treatment may be dosed for at least 3 or 4 weeks. In one embodiment the subject for treatment is dosed for at least 5 or 6 weeks, suitably at least 7 or 8 weeks. 
     In one embodiment a subject for treatment is dosed for 4-8 weeks with at least 2×10 9  cells, wherein said cells are administered once weekly. Suitably a subject for treatment is dosed for 8 weeks with at least 2×10 9  cells (preferably at least 2×10 10  or 2×10 11  cells), wherein said cells are administered once weekly. 
     Administration may be by any suitable technique or route, including but not limited to intravenous injection, intra-arterial injection, intraperitoneal injection, injection into a tumour resection cavity, intrathecal injection, or combinations thereof. Suitably the medicament may be administered intravenously. 
     A white blood cell growth factor may be administered with a medicament of the invention. The administration may be sequential or simultaneous (suitably simultaneous). Suitable white blood cell growth factors may include a granulocyte-macrophage colony-stimulating factor (GM-CSF), a granulocyte colony-stimulating factor (G-CSF), a growth hormone; serotonin, vitamin C, vitamin D, glutamine (Gln), arachidonic acid, AGE-albumin, an interleukin, TNF-alpha, Flt-3 ligand, thrombopoietin, foetal bovine serum (FBS), or combinations thereof. Suitably the white blood cell growth factors may comprise a granulocyte-macrophage colony-stimulating factor (GM-CSF), and a granulocyte colony-stimulating factor (G-CSF), and a growth hormone, and serotonin, and vitamin C, and vitamin D, and glutamine (Gln), and arachidonic acid, and AGE-albumin, and an interleukin, and TNF-alpha, and Flt-3 ligand, and thrombopoietin, and foetal bovine serum (FBS). Particular examples of the foregoing include but are not limited to LEUKINE® brand sargramostim, NEUPOGEN® brand filgrastim, and NEULAST A® brand 5 PEG-filgrastim. 
     Where the medicament is a haematopoietic cell (e.g. a haematopoietic cell culture) the medicament may be administered (e.g. sequentially or simultaneously, preferably simultaneously) with a granulocyte-colony stimulating factor; and a growth hormone; and a serotonin; and an interleukin. In one embodiment a granulocyte precursor cell (e.g. a granulocyte precursor cell culture) is administered (e.g. sequentially or simultaneously, preferably simultaneously) with a granulocyte-colony stimulating factor; and a growth hormone; and a serotonin; and an interleukin. 
     The present invention also provides a kit comprising an in vitro cell culture of haematopoietic cells, a granulocyte, an in vitro cell culture of granulocytes, or a pharmaceutical composition of the invention; and instructions for use of same in medicine. Suitably, the instructions may be for the use of the same in treating a cancer described in any one of the foregoing embodiments. In some embodiments the instructions also detail an appropriate dosage regimen (e.g. as described in a foregoing embodiment). In one embodiment the instructions are for use of said kit in treating cancer, preferably pancreatic cancer. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Singleton, et al., DICTIONARY OF MICROBIOLOGY AND MOLECULAR BIOLOGY, 20 ED., John Wley and Sons, New York (1994), and Hale &amp; Marham, THE HARPER COLLINS DICTIONARY OF BIOLOGY, Harper Perennial, NY (1991) provide the skilled person with a general dictionary of many of the terms used in this disclosure. 
     This disclosure is not limited by the exemplary methods and materials disclosed herein, and any methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of this disclosure. Numeric ranges are inclusive of the numbers defining the range. 
     The headings provided herein are not limitations of the various aspects or embodiments of this disclosure. 
     Other definitions of terms may appear throughout the specification. Before the exemplary embodiments are described in more detail, it is to be understood that this disclosure is not limited to particular embodiments described, and as such may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present disclosure will be defined only by the appended claims. 
     Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within this disclosure. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither or both limits are included in the smaller ranges is also encompassed within this disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in this disclosure. 
     It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a haematopoietic cell” includes a plurality of such candidate agents and reference to “the haematopoietic cell” includes reference to one or more haematopoietic cells and equivalents thereof known to those skilled in the art, and so forth. 
     The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that such publications constitute prior art to the claims appended hereto. 
     The invention will now be described, by way of example only, with reference to the following Figures and Examples. 
    
    
     
       FIGURES 
       Embodiments of the invention will now be described, by way of example only, with reference to the accompanying Figures, in which: 
         FIG. 1  shows cytotoxicity results of Donor Derived Neutrophils (DDNs) from different donors and at different effector to target cell ratios (MTT assay). Differential levels of CKA between donors is maintained at higher effector:target cell ratios. Effector:DDNs; Target:HeLa cells. 
         FIG. 2  shows cytotoxicity results of three CD34+ Stem Cell Derived Neutrophil populations from different donors and at different effector to target cell ratios. Results demonstrate that Stem Cell Derived Neutrophils from different donors have differential CKA. Effector:SCDNs; Target:HeLa cells and PANC-1 (pancreatic cancer). 
         FIG. 3  shows cytotoxicity results of Donor Derived Neutrophils (DDNs) from different donors and at different effector to target cell ratios (xCELLigence Assay). Differential levels of CKA between donors is maintained at higher effector:target cell ratios. Effector:DDNs; Target:HeLa cells. 
         FIG. 4  shows cytotoxicity results of fresh Donor Derived Neutrophils against different cancer cell types and at different effector to target cell ratios. Results demonstrate that DDNs from different donors have differential CKA and have higher CKA against pancreatic cancer cells. Effector:DDNs; Target:HeLa cells (cervical cancer) and PANC-1 cells (pancreatic cancer). 
         FIG. 5  shows selective cytotoxicity of Donor Derived Neutrophils for cancer cell types compared to non-cancer cells and at different effector to target cell ratios. Results demonstrate that DDNs that kill cancer cells have minimal impact on non-cancer cells, confirming selectivity. Effector:DDNs; Target:HeLa cells (cervical cancer) and PANC-1 cells (pancreatic cancer) and MCF-12F (non-cancer cells, normal breast epithelium). 
         FIG. 6  shows cytotoxicity results of CD34+ Stem Cell Derived Neutrophil populations (derived from cord blood stem cells) from five different cultures and at different effector to target cell ratios. Results were generated with the MTT assay and demonstrate that ex vivo generated neutrophils have differential CKA. Effector:SCDNs; Target:HeLa cells. 
         FIG. 7  shows cytotoxicity results of three CD34+ Stem Cell Derived Neutrophil populations against different cancel cell types and at different effector to target cell ratios. Results demonstrate that SCDNs from different donors have differential CKA and have higher CKA against pancreatic cancer cells. Effector:SCDNs; Target:HeLa cells (cervical cancer) and PANC-1 cells (pancreatic cancer). 
         FIG. 8  shows cytotoxicity results of three CD34+ Stem Cell Derived Neutrophil populations from different donors and at different effector to target cell ratios. Results demonstrate that Stem Cell Derived Neutrophils from different donors have differential CKA. Effector:SCDNs; Target:HeLa cells (cervical cancer) and PANC-1 cells (pancreatic cancer). 
         FIG. 9  shows cytotoxicity results of three CD34+ Stem Cell Derived Neutrophil populations from different donors (LC267, LC268, LC269) and at different effector to target cell ratios. Results demonstrate that Stem Cell Derived Neutrophils from different donors have selective cytotoxicity. Effector:SCDNs; Target:HeLa cells (cervical cancer), PANC-1 cells (pancreatic cancer) and MCF-12F cells (non-cancer cells, normal breast epithelium). 
         FIG. 10  shows cytotoxicity results of three CD34+ Stem Cell Derived Neutrophil populations from different donors (LC252, LC253, LC254) and at different effector to target cell ratios. Results demonstrate that Stem Cell Derived Neutrophils from different donors have selective cytotoxicity. Effector:SCDNs; Target:HeLa cells (cervical cancer), PANC-1 cells (pancreatic cancer) and MCF-12F cells (non-cancer cells, normal breast epithelium). 
         FIG. 11  shows cytotoxicity results of three CD34+ Stem Cell Derived Neutrophil cultures together with cytotoxicity results of Donor Derived Neutrophils from the same donor and at different effector to target cell ratios. SCDNs and DDNs from the same donor have similar CKA levels. A similar CKA relationship between DDNs and SCDNs was maintained at different effector to target cell ratios for donor LC253. Effector:SCDNs and DDNs; Target:HeLa cells (cervical cancer). 
         FIG. 12  shows cytotoxicity results of three CD34+ Stem Cell Derived Neutrophil cultures together with cytotoxicity results of fresh Donor Derived Neutrophils from the same donor and at different effector to target cell ratios. SCDNs and DDNs have similar CKA levels. The same CKA relationship between DDNs and SCDNs was maintained at different effector to target cell ratios for donor LC253. Effector:SCDNs and DDNs; Target:HeLa cells (cervical cancer). 
         FIG. 13  shows a comparison of the cytotoxicity of naturally derived and stem cell derived neutrophils over time. The highest CKA (donor LC269) is maintained between DDNs and SCDNs. Effector:SCDNs and DDNs (three different SCDN and DDN cultures); Target:HeLa cells (cervical cancer). 
     
    
    
     EXAMPLES 
     Example 1 
     Recruitment of Donors 
     Donors are pre-selected based on the probability of having neutrophils exhibiting high levels of Cancer Killing Activity (CKA) in a CKA assay described in Example 2. Pre-selection criteria include:
         no serious medical or psychiatric condition that effecting provision of consent or sample collection;   no personal or family history of the cancer(s) being targeted for therapy;   no history of chemotherapy or radiation therapy within three months prior to the sampling date;   aged 18-24;   optionally male (without wishing to be bound by theory, neutrophils from males are believed to exhibit the highest levels of CKA when tested in the CKA assay); and   optionally blood groups 0 or rhesus negative.       

     White Blood Cells (WBCs) are collected by drawing approximately 18 ml of human blood from a donor. The blood is split into three BD Vacutainer™ CPT tubes and centrifuged at 175×g for 35 minutes at 23° C. The mononuclear cell (MN) layer is collected and transferred to a 15 ml conical tube. The MN cells are centrifuged at 420×g for 5 minutes at 23° C., and washed with 10 ml Dulbecco&#39;s Modified Eagle&#39;s Medium (DMED) (Invitrogen, Carlsbad, Calif.)+10% foetal bovine serum (FBS) (Sigma. St. Louis, Mo.). Cells are counted and resuspended in medium to a final concentration of 1.6×10 6  cells/ml. 
     Example 2 
     Testing CKA of Extracted Granulocytes in a CKA Assay 
     Cells are cultured in DMEM+10% FBS in a T25 flask to 80% confluence. The cell line is grown and maintained at 37° C., 8% CO 2 , in T75 cm 2  cell culture flasks in DMEM supplemented with the following ingredients: 10% volume/volume FBS, penicillin (Sigma. St. Louis, Mo.), streptomycin (Sigma. St. Louis, Mo.), and supplemental L-glutamine (Sigma. St. Louis, Mo.). Cultured pancreatic cancer cells (e.g. Capan-2, ATCC HTB-80; Panc 10.05, ATCC CRL-2547; CFPAC-1, ATCC CRL-1918; HPAF-II, ATCC CRL-1997; SW 1990, ATCC CRL-2172; BxPC-3, ATCC CRL-1687; AsPC-1, ATCC CRL-1682; ATCC® TCP-1026TH; SW1990, ATCC CRL-2172; SU.86.86, ATCC CRL-1837; BXPC-3, ATCC CRL-1687; Panc 10.05, ATCC CRL-2547; MIA-PaCa-2, ATCC CRL-1420; PANC-1, ATCC CRL-1469; or ATCC® TCP-2060TH commercially available from the American Type Culture Collection—United Kingdom (U.K.), Guernsey, Ireland, Jersey and Liechtenstein, LGC Standards, Queens Road, Teddington, Middlesex TW11 0LY, UK) are split and passaged before reaching 70% surface confluence in culture flasks. 
     Cells are trypsinised, harvested and counted with Trypan Blue. Assay plates (24-well) are seeded with 8×10 4  pancreatic cancer cells (e.g. pancreatic ductal adenocarcinoma cells) per well in 24-well flat bottom plates. Plates are incubated at 37° C. in 5% CO 2  for 24 hours. Cells are labelled with 2.5 μM CellTracker™ Green for 45 minutes. Fresh medium is added to cells and they are returned to a CO 2 -incubator. 
     The CKA assay is carried out by adding 500 μl of MN cell suspension (8×10 5  granulocytes) to each well in which the pancreatic cancer cells are grown for 24 hours. The cells are mixed and placed in an incubator in 5% CO 2  for 24 hours at 39° C. After a 24-hour incubation, cells are harvested by trypsinisation and centrifuged. Cells are resuspended in 100 μl cold phosphate-buffered saline (PBS), and 125 μl 0.4% Trypan Blue subsequently added. Cells are counted under microscope (using phase contrast and fluorescence microscopy). 
     Granulocytes (e.g. neutrophils) capable of killing at least 70% or at least 80% of the cancer cells (i.e. having at least 70% CKA or 80% CKA, respectively) in the assay are considered particularly suitable for use in treating cancer. 
     Example 3 
     Testing Surface Potential of Haematopoietic Cells and Neutrophils 
     Electrophoresis is used to investigate the surface potential variation in haematopoietic cells (e.g. haematopoietic stem cells, and/or precursor cells) and neutrophils by measuring the electrophoretic mobility. The suspended cells are collected from culture, by mechanical detachment and collection from the culture substrate. Collected cells are redistributed in an electrophoresis buffer solution containing 10 mM Tris-HCl and 291 mM glucose, and are introduced into a rectangular glass electrophoresis chamber. 200V DC is applied across the electrophoresis chamber. The electrophoretic velocity of cells, u, is measured by recording the time needed for cells passing a fixed length with 3 mA under a microscope with a CCD camera. The electrophoretic mobility, p, is calculated by μ=ugS/I, where g is the conductivity of medium, S is the cross-sectional area of the electrophoresis chamber, and/is the current. For each condition typically at least 9 readings are performed to calculate cell electrophoretic mobility. 
     Example 4 
     Extracting Haematopoietic Stem Cells from Peripheral Blood 
     Upon giving consent the donors are given a granulocyte-colony stimulating factor (G-CSF) and/or a granulocyte-macrophage colony-stimulating factor (GM-CSF), e.g. Neupogen® (commercially available from Amgen Inc. USA) to help harvest peripheral haematopoietic stem cells with minimal possible discomfort to donors. Cell surface polypeptide markers are used for identifying long-lasting multipotent stem-cells. Suitably markers may include CD 34 + , CD59 + , Thy1 + , CD38 low/− , C-kit −/low , and lin − . 
     Example 5 
     Expansion and Differentiation of Haematopoietic Cells 
     The haematopoietic cells (e.g. haematopoietic stem cells) are stimulated using a supernatant growth factor suspension, to either develop more stem cells or differentiate into precursor cells (e.g. myeloid or granulocyte progenitor cells) or granulocytes. Suitable neutrophil synthesis methods are disclosed in Lieber et al, Blood, 2004 Feb. 1; 103(3):852-9, and Choi et al, Nat. Protoc., 2011 March; 6(3):296-313. 
     The protocol is composed of four major stages:
         culturing and proliferation of haematopoietic cells;   short-term expansion of multipotent myeloid progenitors with a high dose of granulocyte-macrophage colony-stimulating factor (GM-CSF), a granulocyte colony-stimulating factor (G-CSF), a human growth hormone (HGH); serotonin, vitamin C, vitamin D, glutamine (Gln), arachidonic acid, AGE-albumin, interleukin-3 (IL-3), interleukin 8 (IL-8), Interleukin-4 (IL-4), Interleukin-6 (IL-6), interleukin-18 (IL-18), TNF-alpha, Flt-3 ligand, thrombopoietin, foetal bovine serum (FBS), or combinations thereof; and   directed differentiation of myeloid progenitors into neutrophils, eosinophils, dendritic cells (DCs), Langerhans cells (LCs), macrophages and osteoclasts.       

     Example 6 
     Preparation of Cell Banks 
     Haematopoietic stem cells, granulocyte precursor cells and granulocytes obtainable therefrom, are cryogenically frozen and stored in appropriate cell banks. 
     Example 7 
     Use in Patients for Treating Solid Tumours 
     Stored haematopoietic cells (e.g. haematopoietic stem cells or granulocyte precursor cells obtainable therefrom), and granulocytes (e.g. neutrophils) differentiated therefrom are matched to cancer patients based on their cancer type, blood type (ABO, rhesus and HLA), and/or genetics. Patients may also be matched based on human leukocyte antigen (HLA) similarity. 
     Patients are treated using:
         IV infusion of haematopoietic cells (including haematopoietic stem cells, and granulocyte precursor cells) together with granulocyte-colony stimulating factor, human growth hormone, serotonin, and interleukin into the patient; or   IV infusion of stimulated granulocyte precursor cells (obtainable from haematopoietic stem cells) into the patient. Without wishing to be bound by theory, it is believed that said cells naturally differentiate into granulocytes (e.g. neutrophils) having a high CKA in a CKA assay in vivo; or   direct IV infusion of granulocytes (e.g. neutrophils) having a high CKA in a CKA assay which have been differentiated from haematopoietic cells (e.g. haematopoietic stem cells).       

     Typically, cells are infused once weekly for 8 weeks with a cell volume of 2×10 11  administered per week. Progress of the therapy is monitored and dosing is adapted accordingly. 
     Example 8 
     Treatment of a Patient with Pancreatic Cancer 
     Mary is diagnosed with metastatic pancreatic ductal adenocarcinoma (PDAC) at age 69. Surgery is no longer an option (un-resectable), gemcitabine inadequate in preventing disease progression, and Abraxane or Folfirinox unsuitable on her Oncologist&#39;s recommendation due to the side-effects that will render her incapable of enjoying the time she has left with her family. Mary&#39;s prognosis is 3-6 months to live, and she is desperate to live long enough to see her newly-expected grandchild. 
     Mary is invited to try Leukocyte Infusion Therapy (LIFT). To assess the potential suitability of the therapy, the hospital extracts 20 ml of blood from Mary and sends it for analysis using the Cancer Killing Activity Assay, the assay identifies that the pancreatic cancer killing activity of her granulocytes is less than 5%. Such a low reading demonstrates the inadequacy of her own innate immune system to fight off her cancer which will kill her if the efficacy of the granulocytes in her body is not improved. 
     Mary&#39;s patient notes and assay result are used to find a suitable cancer killing granulocyte match. Mary is blood group A. Mary&#39;s profile is processed using a cell database for a cell bank and suitable granulocytes (that prior to cryogenic freezing exhibit a 70-90% Cancer Killing Activity (CKA) in the Cancer Killing Activity assay of Example 2) are identified. Cryogenically freezing granulocytes helps preserve the CKA and so the cells are able to be dispatched directly to the hospital (The Royal Marsden) with no further testing. Mary is due to visit that week for her first treatment. The hospital appropriately stores the cells. Mary receives her first infusion of 2×10 9  granulocytes having CKA on the 13 th  December under close supervision. Mary is invited back to the hospital 3 days later where she is given an ultrasound scan which reveals significant tumour lysis and no signs of tumour lysis syndrome. The medical team decide to increase the granulocyte dose incrementally over 3 successive treatment sessions until it reaches 2×10 11 . 
     An ultrasound is carried out on the 17 th  January; one week after the 4-week course of four treatments is completed, and shows complete tumour destruction and conversion into scar tissue with good healing taking place. 20 ml of Mary&#39;s blood is taken: i) to assess the presence of metastatic cancer cells in her blood (to confirm complete clearance of the cancer) alongside a biopsy; and ii) to test the Cancer Killing Activity of Mary&#39;s granulocytes (to indicate risk of remission). Mary receives regular check-ups first monthly and then 6-monthly. 
     Two years later a new tumour is discovered on Mary&#39;s pancreas. Her clinicians treat the tumour with radiotherapy and administer a single high dose of LIFT to ensure destruction of any cancer cells that may be present in the blood. Mary enjoys the life that is given back to her and the family she gets to see grow up. 
     After the therapy, the haematopoietic cells (e.g. haematopoietic stem cells) from the cell bank are stimulated to produce more granulocytes (having desired CKA as tested using the assay of Example 2) to replenish stocks. Thus sufficient stock of the required granulocytes for similar patient situations is ensured. 
     Example 9 
     MTT “CKA Assay” 
     MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), a yellow tetrazole which is positively charged and readily penetrates viable eukaryotic cells. Viable cells with active metabolism convert MTT into a purple coloured formazan product (1(E,Z)-5-(4,5-dimethylthiazol-2-yl)-1,3-diphenylformazan) through NAD(P)H-dependent oxidoreductase mitochondrial enzymes, with an absorbance maximum near 570 nm. When cells die, they lose the ability to convert MTT into formazan, thus colour formation serves as a useful and convenient marker of only the viable cells. A solubilization solution is added to dissolve the insoluble purple formazan product into a coloured solution. The absorbance of this coloured solution can be quantified by measuring at wavelength 570 nm by a spectrophotometer. The absorption of a reference wavelength of 690 nm is subtracted from the absorption of the 570 nm wavelength. Therefore, the MTT assay was used to measure how many live cells remained as a way to determine Cancer Killing Activity (CKA)—cytotoxicity to cancer cells. 
     Method for Preparing Hela Target Cells 
     Day 1: 
     1) HeLa cells (a robust type of cervical cancer cell) were cultured and harvested when they reached log phase
 
2) 10000 HeLa cells (target cells) were added to each well of a 96 Flat bottom plate at a final volume of 100 uL
 
3) Target cells were left to adhere overnight before leukocyte (effector cells) addition and all experimental conditions were set in triplicates
 
     Day 2: 
     4) Effector cells were added to the target cells at different ratios (e.g. 1:1, 5:1, 10:1, 50:1, effector to target cells)
 
5) The cells were left to incubate for 16-24 hours at 37° C.
 
6) Target cells alone and target cells in the presence of Triton X were also plated in triplicates as controls for 0% and 100% cytotoxicity, respectively.
 
     After the desired incubation time:
     1) The wells were washed with PBS twice to remove effector cells and dead target cells   2) MTT solution was prepared by dissolving the kit solution 10 times with culture medium, i.e: for 100 wells: take 1000 uL (1 mL) of MTT stock (provided in the kit) and 9000 uL (9 mLs) of culture medium (RPMI-1640) added   3) Add 100 ul/well of the prepared MTT solution at step 2   4) This was incubated for 4 h   5) MTT Solution was removed from all wells and 100 ul/well of the solvent was added (provided in the kit).   6) The formazan crystals were solubized when needed by pipetting and the plate read at 570 and 690 nm. Background absorbance measured at 690 nm was subtracted from absorbance measured at 570 nm.   

     Demonstrating Variable CKA in Donor Neutrophils 
     Leukocyte cones from anonymous blood donors were selected and neutrophils were isolated by Ficoll-Hypaque separation (Oh H, Siano B, Diamond S. Neutrophil Isolation Protocol. Journal of Visualized Experiments: JoVE. 2008; (17):745). These neutrophils were used in the aforementioned MTT assay in ratios of effector to target cell of 1:1, and 5:1. 
       FIG. 1  shows the percentage cytotoxicity recorded by MTT for the different donors. There is a difference between the donors at ratios 1:1 and 5:1. In conclusion, the MTT assay, is able to demonstrate differences in CKA between neutrophils from different donors. 
     Example 10 
     Demonstrating CKA of Stem Cell Derived Neutrophils 
     Culturing Neutrophils from CD34+ Stem Cells 
     We cultured neutrophils from umbilical cord blood derived stem cells expressing the CD34 protein, using the protocol as described by Timmins N E, Palfreyman E, Marturana F, Dietmair S, Luikenga S, Lopez G, et al. Clinical scale ex vivo manufacture of neutrophils from hematopoietic progenitor cells. Biotechnology and bioengineering. 2009; 104(4):832-40. 
     The resulting cultures were tested for neutrophil content using CD11b+ and CD15 markers by Fluorescence-activated cell sorting (FACS). We also measured the production of Reactive Oxygen Specimens (ROS), more specifically the production of superoxide anion (O 2 —) by use of the nitroblue tetrazolium (NBT) assay (kit and protocol commercially-available from Sigma-Aldrich, Catalogue No. 840W-1KT). 
     Since differences in ROS activity were found based on the age of the stem cell derived neutrophils (data not shown), we enumerated three stem cell batches on the same day for consistency/comparability. The results of the FACS derived counting of the proportion of CD11 b+ and CD15+ cells are listed in Table 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Percentage of CD11b+/CD15+ positive neutrophils 
               
            
           
           
               
               
               
            
               
                   
                 CD11b+ CD15+ 
                 CD34+ 
               
               
                 FACS on 26 Sep. 2017 
                 (% of all cells) 
                 (% of all cells) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 CD34+ 14 Sep. 2017 batch 008A 
                 77.8 
                 4.45 
               
               
                 (12 days in culture) 
               
               
                 CD34+ 14 Sep. 2017 batch 709A 
                 76.0 
                 5.1 
               
               
                 (12 days in culture) 
               
               
                 CD34+ 14 Sep. 2017 915 
                 69.2 
                 10.0 
               
               
                 (12 days in culture) 
               
               
                   
               
            
           
         
       
     
     Demonstrating CKA of CD34+ Derived Neutrophils 
     Stem cell derived neutrophils (batches 008A, 709A and 915) were used as effector cells in the CKA MTT assay using HeLa target cells (see Example 9). The effector to target cell ratio is based on CD11b+/CD15+. The results are summarized in  FIG. 2 , which demonstrate that CD34+ stem cell derived neutrophils demonstrate cytotoxicity in a HeLa cell CKA assay and that the results are different between different donors. Batch 008A shows consistently lower cytotoxicity than batches 915 and 709A up to 10:1 effector to target ratio, despite being prepared at the same time as the other batches and cultured in the same way. 
     The results demonstrate that stem cells from different donors can a) be differentiated in vitro to produce neutrophils that demonstrate cancer killing abilities, and b) that this cancer killing activity varies by the source donor. 
     The results support the fact that the cancer killing activity (CKA) by the innate immune system varies by individual and that the same innate variance in CKA seen in neutrophils taken directly from donors via leukocyte cones, is also shown in a donor&#39;s stem cells. By selecting donors with proven high cancer killing activity of their innate immune system, and using their haematopoietic cells (i.e. haematopoietic stem cells) for ex vivo expansion and differentiation, a cell bank can be created with leukocytes with high cancer killing activity to be used in the treatment of cancer. 
     Example 11 
     xCELLigence “CKA Assay” 
     The ACEA Biosciences xCELLigence RTCA DP Analyzer System® was used and the manufacturer&#39;s instructions were followed. The xCELLigence System is a real-time cell analyser, allowing for label-free and dynamic monitoring of cellular phenotypic changes continuously by measuring electrical impedance. The system measures impedance using interdigitated gold microelectrodes integrated into the bottom of each well of the tissue culture E-Plates. Impedance measurements are displayed as Cell Index (CI) values, providing quantitative information about the biological status of the cells, including viability. Impedance-based monitoring of cell viability correlates with cell number and MTT-based readout. The kinetic aspect of impedance-based cell viability measurements provides the necessary temporal information when neutrophils are used to induce cytotoxic effects. In particular, the xCELLigence System can also pinpoint the optimal time points when the neutrophils achieve their maximal effect (where such data is desired), as indicated by the lowest CI values, in cytotoxicity and cell death assays. Typically, 6,000 cancer cells (HeLa or PANC-1) or healthy, non-cancerous cells (MCF-12F) are placed in the bottom of a 16 well plate (the system can read up to 3 plates simultaneously). For the first few hours after cells have been added to a well there is a rapid increase in impedance. This is caused by cells falling out of suspension, depositing onto the electrodes, and forming focal adhesions. If the initial number of cells added is low and there is empty space on the well bottom, cells will proliferate, causing a gradual yet steady increase in Cl. When cells reach confluence the CI value plateaus, reflecting the fact that the electrode surface area that is accessible to bulk media is no longer changing. At this point, which is called the ‘normalization point’, the neutrophils are added (typically in varying effector:target ratios). The percentage of cytolysis is readily calculated using a simple formula: Percentage of cytolysis=((Cell Index no effector −Cell Index effector )/Cell Index no effector )×100. 
     The assay was typically carried out for up to 70 hours and was used in generating the results presented in Examples 12-20. Results presented in Examples 12-19 are maximal % cytolysis achieved during the assay for each cell type. 
     The ratios shown in  FIGS. 3-13  are the ratios of effector (e.g. neutrophil) to target (e.g. cancer cell). Typically ratios of 5:1 or 10:1 neutrophils to cancer cells were used. 
     Example 12 
     Demonstrating Variable CKA in Donor Derived Neutrophils 
       FIG. 3  shows the maximum percentage cytotoxicity recorded by xCELLigence assay for different donors. This assay also shows a difference between the donors at ratios 1:1 and 5:1 (of neutrophils to HeLa cells). In conclusion, the xCELLigence assay is also able to demonstrate differences in CKA between neutrophils from different donors and that this was consistent over different granulocyte to cancer cell ratios. 
     The assay was carried out for up to 40 hours. 
     Example 13 
     Demonstrating CKA of Donor Derived Neutrophils on Different Cancer Cell Types 
     Neutrophils isolated from five different donors were tested for CKA against both HeLa cells (cervical cancer) and PANC-1 cells (pancreatic cancer). 
       FIG. 4  shows the maximum percentage cytotoxicity recorded by the CKA assay (xCELLigence assay) against each cancer cell type and for the different donors. The percentage cytotoxicity against pancreatic cancer cells was higher, which was surprising given that pancreatic cancer is typically one of the most difficult cancers to treat. Again, Donor Derived Neutrophils (DDNs) from different donors were shown to have differential CKA. 
     Example 14 
     Demonstrating the Selectivity of Donor Derived Neutrophil CKA for Cancer Cells 
     Neutrophils isolated from five different donors were tested for CKA against both HeLa cells (cervical cancer), PANC-1 cells (pancreatic cancer) as well as non-cancer MCF-12F cells (normal breast epithelial cells). 
       FIG. 5  shows the maximum percentage cytotoxicity recorded by the CKA assay (xCELLigence assay) for neutrophils from each donor against HeLa and PANC-1 cancer cell lines versus a MCF-12F non-cancer cell line. Advantageously, DDNs were highly selective for cancer cells showing minimal impact on non-cancer cells. 
     Example 15 
     Culturing Neutrophils from CD34+ Stem Cells 
     Further results from culturing neutrophils from umbilical cord blood derived stem cells is presented in Table 2, which shows that neutrophils can be generated from CD34+ haematopoietic stem cells isolated from cord blood. CD34+ is a haematopoietic stem cell marker. CD11b and CD15 are mature neutrophil markers. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Percentage of CD11b+/CD15+ positive neutrophils 
               
            
           
           
               
               
               
               
            
               
                   
                 FACS results 
                   
                 FACS results 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                 Days in 
                   
                 CD11b+/ 
                 Days in 
                   
                 CD11b+/ 
               
               
                   
                 culture 
                 CD34+ 
                 CD15+ 
                 culture 
                 CD34+ 
                 CD15+ 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Batch 1 
                 14 
                 1.32% 
                     61% 
                 18 
                 0.94% 
                 74.3% 
               
               
                 Batch 2 
                 8 
                 4.21% 
                 40.3% 
                 12 
                   3% 
                 60.3% 
               
               
                   
               
            
           
         
       
     
     Example 16 
     Demonstrating CKA of CD34+ Stem Cell Derived Neutrophils (SCDNs) 
     Results were obtained via the xCELLigence assay with further populations of CD34+ Stem Cell Derived Neutrophils ( FIG. 6 ), and were consistent with results obtained via the MTT assay as described above. SCDNs (generated ex vivo) were again shown to have differential CKA, with culture 5 representing low CKA neutrophils and culture 1 representing high CKA neutrophils. 
     Example 17 
     Demonstrating CKA of Stem Cell Derived Neutrophils on Different Cancer Cell Types 
     CD34+ Stem Cell Derived Neutrophils isolated from three different donors were tested for CKA against both HeLa cells (cervical cancer) and PANC-1 cells (pancreatic cancer). 
       FIG. 7  shows the maximum percentage cytotoxicity recorded by the CKA assay (xCELLigence assay) against each cancer cell type and for donors LC267, LC268 and LC269. Similar to the results obtained for DDNs (see Example 14), the percentage cytotoxicity against pancreatic cancer cells was higher than that observed for HeLa cell (at both 5:1 and 10:1 effector to target cell ratios). SCDNs from different donors were also shown to have differential CKA. The assay was carried out for up to 45 hours. 
     Similar results were obtained for SCDNs obtained from donors LC252, LC253 and LC254 ( FIG. 8 ). 
     Example 18 
     Demonstrating the Selectivity of Stem Cell Derived Neutrophils CKA for Cancer Cells 
     Neutrophils derived from CD34+ stem cells of three different donors were tested for CKA against both HeLa cells (cervical cancer), PANC-1 cells (pancreatic cancer) as well as non-cancer MCF-12F cells (normal breast epithelial cells). 
       FIG. 9  shows the maximum percentage cytotoxicity recorded by the CKA assay (xCELLigence assay—carried out for up to 45 hours) against each cancer cell type and non-cancer cell type for donors LC267, LC268 and LC269. Advantageously, SCDNs were highly selective for cancer cells showing minimal impact on non-cancer cells. Similarly to  FIG. 3  showing DDN from the same donors, SCDNs from donor LC269 had the highest CKA with LC268 second, and LC267 showing the lowest CKA. Thus, it can be concluded that CKA is a genetically-defined rather than epigenetically-defined trait. 
     Similar results were obtained for SCDNs of donors LC252, LC253 and LC254 ( FIG. 10 ). 
     Example 19 
     Demonstrating that CKA of Neutrophils is Genetically Encoded 
     Neutrophils isolated from three different donors (DDNs), as well as SCDNs derived from CD34+ stem cells of the same donors were tested for CKA. 
       FIG. 11  shows the maximum percentage cytotoxicity recorded by the CKA assay (xCELLigence assay—carried out for up to 50 hours) against HeLa cells for donors LC252, LC253 and LC254 for the DDNs and SCDNs. Surprisingly, the SCDNs demonstrated a CKA which was highly similar to that of the DDNs from the same donor, again demonstrating that CKA is encoded at the genetic level. Similarly to  FIG. 10 , donor LC253 provided neutrophils (and SCDNs) with the highest CKA, while donors LC252 and LC254 provided neutrophils (and SCDNs) having lower CKA. 
     This demonstrates that donors found to have neutrophils (e.g. DDNs) with a high CKA may also be used as a source of CD34+ stem cells which can be differentiated into neutrophils (e.g. SCDNs) with similarly high CKA. 
     Similar results were obtained for SCDNs of donors LC267, LC268 and LC269 ( FIG. 12 —carried out for up to 45 hours). 
     Example 20 
     Demonstrating that SCDNs Kill Cancer Cells More Rapidly than DDNs 
     The CKA of SCDNs and DDNs of donors LC267, LC268, and LC269 was determined up to a period of 45 hours. The assay was carried out according to Example 11. 
     Surprisingly, the results ( FIG. 13 ) show that SCDNs kill cancer cells more rapidly than DDNs from the same donor. The SCDNs of donor LC269 showed particularly rapid cancer killing efficacy, killing ˜50% of cancer cells in ˜18 hours (compared with 35% for DDNs), with half-maximal kill for SCDNs occurring within 10 hours (compared with negligible killing at this time for DDNs). 
     Example 21 
     Isolation of High-Density Neutrophils 
     10 ml of heparinized (20 U/ml) human blood is mixed with an equal volume of 3% Dextran T500 in saline and incubated for 30 minutes at room temperature to sediment erythrocytes. A 50 ml conical polypropylene tube is prepared with 10 ml sucrose 1.077 g/ml and slowly layered with a leukocyte-rich supernatant on top of the 1.077 g/ml sucrose layer prior to centrifuging at 400×g for 30 minutes at room temperature without brake. The high-density neutrophils (HDN) appear in the pellet. Low-density neutrophils (LDN) co-purify with monocytes and lymphocytes at the interface between the 1.077 g/ml sucrose layer and plasma. 
     The HDNs may be tested in a CKA assay described herein. Haematopoietic cells are suitably obtained from a donor having HDNs. 
     Example 22 
     Differentiation of Induced Pluripotent Stem Cells (iPSCs) into Neutrophils with High CKA 
     A donor comprising neutrophils with high CKA is identified. A somatic cell (e.g. fibroblast) is isolated from the donor and used to establish a culture of iPSCs. The iPSCs are differentiated into mature neutrophils, e.g. using the protocol as described by Sweeney C L, Merling R K, Choi U, Priel D B, Kuhns D B, Wang H and Malech H L, Generation of functionally mature neutrophils from induced pluripotent stem cells. Neutrophil Methods and Protocols, Methods in Molecular Biology. 2014; 1124:189-206, and Sweeney et al (2016), Stem Cells, 34(6), 1513-1526 (the teaching of which is incorporated herein by reference). 
     The resulting mature neutrophils are shown to have similar CKA levels to those of the DDNs and SCDNs from HSCs (as tested by both the MTT and xCELLigence assay) from the same donor. 
     The mature neutrophils are subsequently injected into the donor from which the iPSCs have been originally derived, and do not provoke any immune response. 
     All publications mentioned in the above specification are herein incorporated by reference. Various modifications and variations of the described methods and system of the present invention will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. Although the present invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in biochemistry and biotechnology or related fields are intended to be within the scope of the following claims. 
     CLAUSES 
     
         
         1. An in vitro cell culture of haematopoietic cells, wherein said haematopoietic cells differentiate to form granulocytes characterised by:
       a. a surface potential defined by an electrophoretic mobility of at least 1.0 μm·cm/volt·sec; and   b. the ability to kill cancer cells.   
     
         2. An in vitro cell culture of haematopoietic cells, wherein said haematopoietic cells differentiate to form granulocytes characterised by:
       a. a density of at least 1.077 g/ml; and   b. the ability to kill cancer cells.   
     
         3. An in vitro cell culture of haematopoietic cells, wherein said haematopoietic cells differentiate to form granulocytes characterised by:
       a. expression or activity of toll-like receptors; and/or an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2; and   b. the ability to kill cancer cells.   
     
         4. An in vitro cell culture according to clause 1, wherein the haematopoietic cells differentiate to form granulocytes further characterised by:
       a. a density of at least 1.077 g/ml; and/or   b. expression or activity of toll-like receptors; and/or an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2.   
     
         5. An in vitro cell culture according to clause 3 or 4, wherein the granulocytes are characterised by expression or activity of toll-like receptors; and an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and CXCR2. 
         6. An in vitro cell culture according to any one of the preceding clauses, wherein the cell culture is enriched for the haematopoietic cells. 
         7. An in vitro cell culture according to any one of the preceding clauses, wherein at least 70% of the cells in the in vitro cell culture are the haematopoietic cells. 
         8. An in vitro cell culture according to any one of the preceding clauses, wherein the haematopoietic cells are obtainable from a donor, preferably a human donor. 
         9. An in vitro cell culture according to clause 8, wherein the donor is a male donor. 
         10. An in vitro cell culture according to clause 8 or 9, wherein the donor is aged 18 to 25. 
         11. An in vitro cell culture according to any one of the preceding clauses, wherein the haematopoietic cells have a greater surface potential than otherwise identical haematopoietic cells that differentiate to form granulocytes having a surface potential defined by an electrophoretic mobility of less than 1.0 μm·cm/volt·sec and/or a reduced ability to kill cancer cells, when compared to feature b defined in clause 1, 2, or 3. 
         12. An in vitro cell culture according to any one of the preceding clauses, wherein the haematopoietic cells have a surface potential defined by an electrophoretic mobility of at least 1.0 μm·cm/volt·sec or at least 2.0 μm·cm/volt·sec or at least 2.5 μm·cm/volt·sec or at least 3.0 μm·cm/volt·sec. 
         13. An in vitro cell culture according to any one of the preceding clauses, wherein the granulocytes have a surface potential defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec or at least 2.5 μm·cm/volt·sec or at least 3.0 μm·cm/volt·sec. 
         14. An in vitro cell culture according to any one of the preceding clauses, wherein the granulocyte is a neutrophil. 
         15. A method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
       a. measuring a surface potential of a granulocyte cell obtainable from a donor; and   b. selecting a haematopoietic cell from said donor when the measured surface potential is defined by an electrophoretic mobility of at least 1.0 μm·cm/volt·sec.   
     
         16. A method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
       a. measuring the density of a granulocyte cell obtainable from a donor; and   b. selecting a haematopoietic cell from said donor when the measured density of the granulocyte is at least 1.077 g/ml.   
     
         17. A method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
       a. detecting the expression or activity of toll-like receptors; programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2 on a granulocyte cell obtainable from a donor; and   b. selecting a haematopoietic cell from said donor when the toll-like receptors are expressed or active; and/or programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2 are not expressed or are inactive.   
     
         18. A method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
       a. measuring a surface potential of the haematopoietic cell; and   b. selecting a haematopoietic cell that has a greater surface potential than an otherwise identical haematopoietic cell that differentiates to form a granulocyte having a surface potential defined by an electrophoretic mobility of less than 1.0 μm·cm/volt·sec and/or has a reduced ability to kill cancer cells.   
     
         19. A method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
       a. measuring the density of a haematopoietic cell; and   b. selecting a haematopoietic cell that has a density greater than an otherwise identical haematopoietic cell that differentiates to form a granulocyte having a density of less than 1.077 g/ml and/or has a reduced ability to kill cancer cells   
     
         20. A method according to any one of clauses 15-19, wherein the haematopoietic cell has a surface potential defined by an electrophoretic mobility of at least 1.0 μm·cm/volt·sec. 
         21. A method according to any one of clauses 15-20, wherein the haematopoietic cell has a surface potential defined by an electrophoretic mobility of at least 2.0 μm·cm/volt·sec or at least 2.5 μm·cm/volt·sec or at least 3.0 μm·cm/volt·sec. 
         22. A method according any one of clauses 15-21, wherein the surface potential is determined by electrophoresis. 
         23. A method according to any one of clauses 15-22 further comprising discarding haematopoietic cells that are not selected in step b. of any one of clauses 15-19. 
         24. A method according to any one of clauses 15-23, wherein the haematopoietic cell is a haematopoietic stem cell. 
         25. A method according to any one of clauses 15-24, wherein the haematopoietic cell is a granulocyte precursor cell, such as a common myeloid progenitor cell, a myeloblast, a N. promyelocyte, a N. myelocyte, a N. metamyelocyte, a N. band, or combinations thereof. 
         26. A method according to any one of the clauses 15-25, wherein the granulocyte is a neutrophil. 
         27. A method according to any one of clauses 15-26 further comprising differentiating the haematopoietic cell into a granulocyte. 
         28. A method according to any one of clauses 16-27, wherein the haematopoietic cell is obtainable from a donor, preferably a human donor. 
         29. A method according to any one of clauses 15-28, wherein the donor is a male donor. 
         30. A method according to any one of clauses 15-29, wherein the donor is aged 18 to 25. 
         31. An in vitro method for selecting a haematopoietic cell suitable for use in treating cancer, said method comprising:
       a. admixing a granulocyte obtainable from a donor with a cell line to form an admixture;   b. incubating said admixture;   c. measuring the % of cancer cells killed in said admixture; and   d. selecting a haematopoietic cell from said donor when said granulocyte kills at least 70% of the cancer cells in the admixture.   
     
         32. Use of a surface potential of a haematopoietic cell, for selecting a cell that can be differentiated into a granulocyte that is suitable for treating cancer, wherein the surface potential is greater than the surface potential of an otherwise identical haematopoietic cell that differentiates to form a granulocyte having a surface potential defined by an electrophoretic mobility of less than 1.0 μm·cm/volt·sec and/or has a reduced ability to kill cancer cells. 
         33. Use according to clause 32, wherein the haematopoietic cell has a surface potential defined by an electrophoretic mobility of at least 1.0 μm·cm/volt·sec, or at least 2.0 μm·cm/volt·sec, or at least 2.5 μm·cm/volt·sec, or at least 3.0 μm·cm/volt·sec. 
         34. An in vitro method for selecting a granulocyte suitable for use in treating pancreatic cancer, said method comprising:
       a. admixing a granulocyte with a pancreatic cancer cell line to form an admixture;   b. incubating said admixture;   c. measuring the % of pancreatic cancer cells killed in said admixture; and   d. selecting a granulocyte that kills at least 70% of the pancreatic cancer cells in the admixture.   
     
         35. An in vitro method according to clause 34, wherein the pancreatic cancer cell line is a pancreatic ductal adenocarcinoma cell line. 
         36. An in vitro method for selecting a granulocyte suitable for use in treating cancer, said method comprising:
       a. admixing a granulocyte with a plurality of different cancer cell lines to provide a plurality of admixtures;   b. incubating said admixtures;   c. measuring the % of cancer cells killed in said admixtures; and   d. selecting a granulocyte as suitable for use in treating a cancer of the same type/subset as the cancer cell line, when said granulocyte kills at least 70% of the cancer cells in the admixture.   
     
         37. An in vitro method according to any one of clauses 34-36 further comprising discarding granulocytes that kill less than 70% of the cancer cells in the admixture. 
         38. An in vitro method according to any one of clauses 34-37, wherein the granulocyte is obtainable from a donor, preferably a human donor. 
         39. An in vitro method according to any one of clauses 34-38, wherein the granulocyte is obtainable from a subject having a cancer of a different type/subset to the cancer cell line(s) used in the method. 
         40. An in vitro method according to any one of clauses 34-39, wherein the cancer cell line(s) is one or more selected from: a pancreatic cancer cell line, a liver cancer cell line, an oesophageal cancer cell line, a stomach cancer cell line, a cervical cancer cell line, an ovarian cancer cell line, a lung cancer cell line, a bladder cancer cell line, a kidney cancer cell line, a brain cancer cell line, a prostate cancer cell line, a myeloma cancer cell line, a non-Hodgkin&#39;s lymphoma (NHL) cell line, a larynx cancer cell line, a uterine cancer cell line, or a breast cancer cell line. 
         41. An in vitro method according to any one of clauses 38-40, further comprising obtaining a haematopoietic cell from the donor from whom the selected granulocyte is obtainable. 
         42. A granulocyte obtainable by a method according to any one of clauses 34-41. 
         43. A method comprising differentiating an in vitro cell culture of haematopoietic cells according to any one of clauses 1-14, or haematopoietic cells obtainable according to a method of any one of clauses 15-31 into granulocytes. 
         44. An in vitro cell culture of granulocytes obtainable by a method of clause 43, wherein said cell culture is enriched with granulocytes having:
       a. a surface potential defined by an electrophoretic mobility of at least 1.0 μm·cm/volt·sec; and   b. the ability to kill cancer cells.   
     
         45. An in vitro cell culture of granulocytes obtainable by a method of clause 43, wherein said cell culture is enriched with granulocytes having:
       a. a density of at least 1.077 g/ml; and   b. the ability to kill cancer cells.   
     
         46. An in vitro cell culture of granulocytes obtainable by a method of clause 43, wherein said cell culture is enriched with granulocytes having:
       a. expression or activity of toll-like receptors; and/or an absence of expression or inactivity of: programmed death 1 (PD-1) receptor; CD115; CD224; CXCR1; and/or CXCR2; and   b. the ability to kill cancer cells.   
     
         47. A pharmaceutical composition comprising:
       a. a haematopoietic cell or a granulocyte; and   b. a granulocyte-macrophage colony-stimulating factor (GM-CSF), a granulocyte colony-stimulating factor (G-CSF), a growth hormone; serotonin, vitamin C, vitamin D, glutamine (Gln), arachidonic acid, AGE-albumin, an interleukin, TNF-alpha, Flt-3 ligand, thrombopoietin, foetal bovine serum (FBS), or combinations thereof.   
     
         48. An in vitro cell culture of haematopoietic cells according to any one of clauses 1-14, or a granulocyte according to clause 42, or an in vitro cell culture of granulocytes according to clauses 44-46, or a pharmaceutical composition according to clause 47, for use in treating cancer. 
         49. Use of an in vitro cell culture of haematopoietic cells according to any one of clauses 1-14, or a granulocyte according to clause 42, or an in vitro cell culture of granulocytes according to any one of clauses 44-46, or a pharmaceutical composition according to clause 47, in the manufacture of a medicament for treating cancer. 
         50. A method for treating cancer comprising: administering to a subject in need thereof an in vitro cell culture of haematopoietic cells according to any one of clauses 1-14, or a granulocyte according to clause 42, or an in vitro cell culture of granulocytes according to any one of clauses 44-46, or a pharmaceutical composition according to clause 47. 
         51. An in vitro cell culture of haematopoietic cells according to any one of clauses 1-14, or a granulocyte according to clause 42, or an in vitro cell culture of granulocytes according to any one of clauses 44-46, or a pharmaceutical composition according to clause 47 for use, use or method according to any one of clauses 48-50, wherein the cancer is a solid tumour cancer. 
         52. An in vitro cell culture of haematopoietic cells according to any one of clauses 1-14, or a granulocyte according to clause 42, or an in vitro cell culture of granulocytes according to any one of clauses 44-46, or a pharmaceutical composition according to clause 47 for use, use or method according to any one of clauses 48-50, wherein the cancer is one or more of: pancreatic cancer, liver cancer, oesophageal cancer, stomach cancer, cervical cancer, ovarian cancer, lung cancer, bladder cancer, kidney cancer, brain cancer, prostate cancer, myeloma cancer, non-Hodgkin&#39;s lymphoma (NHL), larynx cancer, uterine cancer, or breast cancer. 
         53. An in vitro method for selecting a subject for treatment with an in vitro cell culture of haematopoietic cells according to any one of clauses 1-14, or a granulocyte according to clause 42, or an in vitro cell culture of granulocytes according to any one of clauses 44-46, or a pharmaceutical composition according to clause 47, said method comprising:
       a. admixing a granulocyte from said subject with a cancer cell line;   b. incubating said admixture;   c. measuring the % of cancer cells killed in said admixture; and   d. selecting a subject for treatment with an in vitro cell culture of haematopoietic cells according to any one of clauses 1-14, or a granulocyte according to clause 42, or an in vitro cell culture of granulocytes according to any one of clauses 44-46, or a pharmaceutical composition according to clause 47, when the granulocyte from said subject kills less than 70% of the cancer cells in the admixture.   
     
         54. An in vitro method according to clause 53, wherein the subject is selected for treatment if the granulocyte from said subject kills less than 50% or less than 25% (preferably less than 10% or 5%) of the cancer cells in the admixture. 
         55. A cell bank comprising an in vitro cell culture of haematopoietic cells according to any one of clauses 1-14, or a granulocyte according to clause 42, or an in vitro cell culture of granulocytes according to any one of clauses 44-46, or a pharmaceutical composition according to clause 47. 
         56. A kit comprising:
       a. in vitro cell culture of haematopoietic cells according to any one of clauses 1-14, or a granulocyte according to clause 42, or an in vitro cell culture of granulocytes according to any one of clauses 44-46, or a pharmaceutical composition according to clause 47; and   b. instructions for use of same in medicine.   
     
         57. A kit according to clause 56, wherein said instructions are for use of same in treating cancer, preferably pancreatic cancer.