A method for determining the presence or activity of at least one promoter in a cancerous biological sample relative to a non-cancerous biological sample, comprising; mapping an isolated nucleic acid comprising at least one promoter sequence obtained from said cancerous biological sample against a reference nucleic acid obtained from said non-cancerous biological sample to obtain a read per kilo-base per million (RPKM) value or fragments per kilo-base per million (FPKM) value for said at least one promoter; and determining the differential activity of the at least one promoter sequence in the nucleic acid relative to the activity of the at least one promoter in the reference nucleic acid sequence using said RPKM or FPKM value wherein the step of determining the differential activity of the at least one promoter sequence comprises determining that the RKPM or FPKM value for the at least one promoter in the nucleic acid obtained from the cancerous biological sample is: (i) greater than between a 1 to 20-fold, such as a 1-fold, 2-fold, 3-fold, 4-fold or 5-fold, change in mean RPKM or FPKM value relative to the RPKM or FPKM value of the at least one promoter in the reference nucleic acid obtained from the non-cancerous biological sample; and (ii) greater than a 0.1 RPKM or FPKM range relative to the RPKM or FPKM value of the at least one promoter in the reference nucleic acid obtained from the non-cancerous biological sample; wherein the cancer is gastric cancer; and wherein the nucleic acid is isolated from said cancerous biological sample by immunoprecipitation of chromatin, wherein said nucleic acid comprises said at least one promoter, the immunoprecipitation being achieved by an antibody specific for a modified histone protein comprising at least one histone modification selected from the group consisting of H3K4me3, H3K4me1, and H3K27ac. mapping an isolated nucleic acid comprising at least one promoter sequence obtained from said cancerous biological sample against a reference nucleic acid obtained from said non-cancerous biological sample to obtain a read per kilo-base per million (RPKM) value or fragments per kilo-base per million (FPKM) value for said at least one promoter; and determining the differential activity of the at least one promoter sequence in the nucleic acid relative to the activity of the at least one promoter in the reference nucleic acid sequence using said RPKM or FPKM value wherein the step of determining the differential activity of the at least one promoter sequence comprises determining that the RKPM or FPKM value for the at least one promoter in the nucleic acid obtained from the cancerous biological sample is: (i) greater than between a 1 to 20-fold, such as a 1-fold, 2-fold, 3-fold, 4-fold or 5-fold, change in mean RPKM or FPKM value relative to the RPKM or FPKM value of the at least one promoter in the reference nucleic acid obtained from the non-cancerous biological sample; and (ii) greater than a 0.1 RPKM or FPKM range relative to the RPKM or FPKM value of the at least one promoter in the reference nucleic acid obtained from the non-cancerous biological sample; wherein the cancer is gastric cancer; and wherein the nucleic acid is isolated from said cancerous biological sample by immunoprecipitation of chromatin, wherein said nucleic acid comprises said at least one promoter, the immunoprecipitation being achieved by an antibody specific for a modified histone protein comprising at least one histone modification selected from the group consisting of H3K4me3, H3K4me1, and H3K27ac. (i) greater than between a 1 to 20-fold, such as a 1-fold, 2-fold, 3-fold, 4-fold or 5-fold, change in mean RPKM or FPKM value relative to the RPKM or FPKM value of the at least one promoter in the reference nucleic acid obtained from the non-cancerous biological sample; and (ii) greater than a 0.1 RPKM or FPKM range relative to the RPKM or FPKM value of the at least one promoter in the reference nucleic acid obtained from the non-cancerous biological sample;