Apaf-1基因甲基化及表达在结直肠癌发生中的作用

THE METHYLATION AND EXPRESSIONS OF APAF-1 IN DEVELOPMENT OF CRC

目的探讨Apaf-1基因甲基化及表达在结直肠癌(colorectal cancer,CRC)发生中的作用。方法应用半定量RT-PCR和甲基化特异性PCR方法,分析40例CRC及癌旁正常组织中Apaf-1(apoptotic protease activating factor-1)基因的表达及启动子区甲基化情况。结果65%(26/40)的CRC组织Apaf-1表达明显下调,与癌旁正常组织相比差异有统计学意义(P<0.05)。Apaf-1基因与患者的性别及浸润深度差异无统计学意义(P>0.05),与患者的病理组织分化程度、淋巴结转移与否、临床TNM分期差异有统计学意义(P<0.05)。在Apaf-1基因表达明显下调的26例CRC中20例出现甲基化,表达水平无明显变化的14例CRC中5例出现甲基化,二者对比差异有统计学意义(P<0.05)。40例癌旁正常对照组织未检测到Apaf-1基因甲基化,提示甲基化是Apaf-1基因表达下调的主要原因。结论Apaf-1基因与CRC的发生发展相关,启动子区甲基化是该基因失活的重要发生机制。

Objective To investigate the methylation 1 （ Apaf - 1 ） in development of colorectal cancer （CRC）. and expressions of apoptotic protease activating factor - Methods Methylation and expressions of Apaf - 1 gene were analyzed by RT - PCR and methylation specific PCR （MSP） in 40 cases of CRC tumor tissues and paracarcinoma normal tissues. Results Apaf - 1 gene expression was down - regulated in 65 % （26/40） of patients with CRC tissues（ P 〈 0.05 ）. Apaf- 1 expression level specially related with gander of patients; there is no significant rela- tionships with the depth of invasion, pathologic differentiation degree and the metastasis of lymph nods. But the TNM clinical stages have shown significant differentiates. 20 cases of Apaf - 1 gene methylation were detected in 27 cases with obvious down - regulation expression of Apaf- 1, but 5 cases of methylation were found in 14 cases in which the expression of Apaf- 1 gene had no obvious change. The two groups has shown significant difference （P 〈 0.05 ）. Methylation was not found in 45 cases of normal paracarcinoma tissues. Conclusion This study may show the association between Apaf- 1 gene and CRC development,and DNA methylation in promoter region that participates in the decreased expression of Apaf - 1 gene in CRC.