In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Q: Context: The modern multimodality therapeutic approach to Wilms tumor (WT), combining surgery with radiotherapy and chemotherapy results in high cure rates even for high stage disease. However, the combination of radiotherapy and chemotherapy is associated with severe early and late complications such as neutropenic sepsis, growth retardation and secondary malignancies. Therefore, novel therapeutic strategies, which would decrease the treatment burden, are required. We studied the expression of erbB2 growth factor receptor in WT cells as well as its role as a tumor therapeutic target in an in vivo xenograft model of Wilms tumor.', 'Paraffin embedded pathological samples from 14 different WT cases as well as xenografts derived thereof were immunostained with anti-erbB2 monoclonal antibody. The immunostaining was graded in comparison to a known positive control (breast cancer) and was scored by the intensity of staining (0 to +3) multiplied by the percentage of cells expressing the antigen. The expression of erbB2 in the human WT xenograft was verified also by fluorescence activated cell sorter analysis. In addition, nude mice bearing established subcutaneous human WT xenografts were treated with either 3 intraperitoneal injections of N29 anti-erbB2 monoclonal antibody or irrelevant antibody.', 'All of the authentic human pathological samples, except 1 anaplastic WT as well the WT xenografts (at different stages), expressed erbB2. Expression was also observed in WT metastasis and in tumors which out grew chemotherapy. Systemic administration of anti-erbB2 monoclonal antibody inhibited and even prevented the growth of WT xenograft in vivo.\Question: Is erbB2 a tumor associated antigen and a suitable therapeutic target in Wilms tumor?

A: ErbB2 is a tumor associated antigen in WT. Being expressed in almost all tumor stages, our in vivo model suggests that erbB2 may serve as a WT therapeutic target. Further work is needed to establish the role of erbB2 in the disease and its potential use in decreasing current treatment burden.
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Q: Context: Cord blood (CB) hematopoietic stem cell transplantation has often been limited by the scarcity of stem cells. Therefore, the number of CB hematopoietic stem/progenitor cells (HSPCs) should be increased while maintaining the stem cell characteristics.', 'We designed an ex vivo culture system using endothelial progenitor cells (EPCs) as stroma to determine the capacity of expanding CB-HSPCs in a defined medium, the effect on engraftment of the expanded cells in a mouse model and the underlying mechanism.', "After 7 days of culture, compared with those cultured with cytokines alone (3.25 0.59), CD34+ cells under contact and non-contact co-culture with EPCs were expanded by 5.38 0.61 (P = 0.003) and 4.06 0.43 (P = 0.025)-fold, respectively. Direct cell-to-cell contact co-culture with EPCs resulted in more primitive CD34+ CD38- cells than stroma-free culture (156.17 21.32 versus 79.12 19.77-fold; P = 0.010). Comparable engraftment of day 7 co-cultured HSPCs with respect to HSPCs at day 0 in nonobese diabetic-severe combined immunodeficiency disease (NOD/SCID) mice was measured as a percentage of chimerism (13.3% 11.0% versus 16.0% 14.3%; P = 0.750). EPCs highly expressed interleukin 6 (IL6) and angiopoietin 1 (ANGPT1), the hematopoietic- related cytokines. A higher transcriptional level of WNT5A genes in EPCs and co-cultured HSPCs suggests that the activation of Wnt signaling pathway may play a role in HSPCs' expansion ex vivo.\Question: Do endothelial progenitor cells promote efficient ex vivo expansion of cord blood-derived hematopoietic stem/progenitor cells?

A: These data demonstrated that EPCs improve the CD34+ population but do not compromise the repopulating efficacy of the amplified HSPCs, possibly via cytokine secretion and Wnt signaling pathway activation.
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Q: Context: To study the ability of human spermatogonial stem cells (hSSCs) to proliferate invitro under mouse spermatogonial stem cell (mSSC) culture conditions.', 'Experimental basic science study.', 'Reproductive biology laboratory.', 'Cryopreserved testicular tissue with normal spermatogenesis obtained from three donors subjected to orchiectomy due to a prostate cancer treatment.', 'Testicular cells used to create invitro cell cultures corresponding to the following groups: [1] unsorted human testicular cells, [2] differentially plated human testicular cells, and [3] cells enriched with major histocompatibility complex class 1 (HLA', 'Analyses and characterization including immunocytochemistry and quantitative reverse-transcription polymerase chain reaction for somatic and germ cell markers, testosterone and inhibin B quantification, and TUNEL assay.', 'Putative hSSCs appeared in singlets, doublets, or small groups of up to four cells invitro only when testicular cells were cultured in StemPro-34 medium supplemented with glial cell line-derived neurotrophic factor (GDNF), leukemia inhibitory factor (LIF), basic fibroblast growth factor (bFGF), and epidermal growth factor (EGF). Fluorescence-activated cell sorting with HLA\Question: Do human spermatogonial stem cells display limited proliferation in vitro under mouse spermatogonial stem cell culture conditions?

A:
We found that hSSCs show limited proliferation invitro under mSSC culture conditions. Coculture of HLA
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