Abstract:

[Abstract] Objective  To investigate the promoter methylation of apoptosis protease activating factor-1 (Apaf-1) and its association with the protein expression of enhancer of zeste homolog 2 (EZH2) in esophageal squamous cell carcinoma (ESCC). Methods  The methylation-specific PCR (MSP) method was used to examine the methylation status of Apaf-1 in 128 ESCC patients, and immunohistochemistry method was used to detect the protein expression of Apaf-1 and EZH2 in tumors and corresponding normal tissues. Results  The frequencies of Apaf-1 methylation in ESCC tumor tissues (52.3%, 67/ 128) were significantly higher than those in normal tissues (4.7%, 6/128) (P < 0.01), which was associated with TNM stage. The positive protein expression of Apaf-1 was significantly decreased in ESCC tumor tissues (41.4%, 53/128) compared with that of paired normal tissues (94.5%, 21/128) (P < 0.01). The positive protein expression of EZH2 was significantly increased in ESCC tumor tissues (72.7%, 93/128) than that of paired normal tissues (12.5%, 16/128) (P < 0.01). The protein expressions of Apaf-1 and EZH2 were associated with the TNM stage and pathological differentiation in ESCC patients (P < 0.01). The methylation status of Apaf-1 in ESCC was negatively correlated with the positive protein expression. The protein expressions of Apaf-1 and EZH2 were negatively correlated in ESCC. Conclusion  Promoter hypermethylation of Apaf-1 and the higher protein expression of EZH2 may play important role in esophageal squamous cell carcinoma.