Methylation quantification of the 12 candidate genes revealed significantly higher methylation proportion for promoter regions of APC, BIN1, BMP6, BRCA1, CST6, ESR-b, P16, PTEN and TIMP3 in primary tumor tissue versus matched normal tissue (P < 0.05, P < 0.05, P < 0.01, P < 0.0001, P < 0.01, P < 0.01, P < 0.05, P < 0.05, P < 0.01 ; respectively). The gene discussed is BRCA1; the disease is neoplasm.