Abstract: BACKGROUND ＆ AIM: Inhibitory effects of 5-azacytidine on the proliferation of human breast cancer cell line Bcap-37 and its mechanism were investigated. MATERIAL AND METHODS： After treatment of Bcap-37 cells with 5-azacytidine, cell proliferation was analyzed by cell counting . The methylation and unmethylation status of RASSF1A gene were detected by methylation special PCR(MSP)and RASSF1A mRNA expression was detected by RT-PCR. RESULTS: After treatment with 5-azacytidine(>5 μmol/L),the Bcap-37 cells growth rate was decreased in a dose-dependent manner. Demethylation of RASSF1A gene occurred and RASSF1A mRNA expression was increased. CONCLUSION： 5-Azacytidine could effectively enhance RASSF1A gene demethylation and enhance the expression of RASSF1A mRNA and inhibit cell growth.

Key words: breast cancer cell, RAS association domain family1A Gene, gene methylation, 5-Azacytidine, methylation special PCR