promoter methylation and mrna expression of apaf-1 gene in breast cancer

Background: apoptosis protease-activating factor-1 (apaf-1) is an important tumor suppressor gene, which plays a central function in dna damage-induced apoptosis. the present study aimed to examine the epigenetic regulation of apaf-1 in breast cancer to gain a better understanding of tumor biology. methods: the promoter methylation of apaf-1 gene was determined by methylation-specific polymerase chain reaction (ms-pcr) method, using 63 paraffin-embedded breast tumors and their corresponding normal tissues as the control tissue samples. expression analysis was performed on all tissue samples, using quantitative pcr (qpcr) method. results: significant down-regulation was observed for apaf-1 expression among tumor tissues, compared to the control group (p = 0.011). apaf-1 promoter hypermethylation was more frequent in breast tumors in comparison with normal tissues (57% vs. 21%; p = 0.001) and was correlated with gene mrna level (p < 0.05). methylation level increased from the primary to the advanced stage of the disease (p = 0.001), which suggests the possible role of apaf-1 methylation in disease progression. conclusions: methylation is an important epigenetic factor which might contribute to the down-regulation of apaf-1 gene in breast tumor tissues.