结直肠癌中p16基因的甲基化改变与蛋白表达的关系

Study on the aberrant methylation and protein of p16 gene in patients with colorectal cancer

目的 检测结直肠癌患者肿瘤组织中p16基因启动子区异常甲基化改变及蛋白表达情况,探讨其与结直肠癌发生发展与临床的关系。方法 采用甲基化特异PCR(MSP)和免疫组织化学链霉素过氧化物酶(SP)方法,对32份结直肠癌标本p16基因甲基化改变及蛋白表达情况进行检测分析。结果 p16甲基化阳性率为40.6％;p16蛋白表达阳性率75.0％;在病理分期中,DukesC、D期患者肿瘤组织中p16甲基化发生率63.0％,p16蛋白表达发生率为69.0％;DukesA、B期患者p16甲基化发生率为25.0％,p16蛋白表达阳性率为81.0％;在组织分化程度中,低分化癌中的p16甲基化阳性率为100.0％,p16蛋白表达阳性率为20.0％;在高、中分化癌中,p16甲基化的阳性率为30.0％,p16蛋13表达阳性率为85.0％;淋巴结转移癌患者肿瘤组织中p16基因甲基化阳性率为63.0％,淋巴结未转移的阳性率为25.0％;在肿瘤部位中,直肠癌p16蛋白表达阳性率为65.0％,结肠癌的阳性率为100.0％。结论 p16甲基化的改变可能影响p16蛋白的表达;p16甲基化、蛋白表达与结直肠癌的发生发展密切相关,p16甲基化和蛋白表达是结直肠癌患者诊断及预后的候选标志物之一。

Objective To explore whether hypermethylation in the promoter of p16 gene and protein of p16 were associated with development and clinicopathological characteristics of colorectal cancer. Methods Methylation-specific PCR ( MSP) and immunohistochemistry SP were used to detected hypermethylation of p16 gene and p16 protein in tumor tissues from 32 patients with colorectal cancer. Results The hypermethylation of p16 gene was detected in 40. 6% of tumor tissues. The protein of p16 promoter was detected in 75% of tumor tissues. The hypermethylation of p16 gene was detected in 63% in Dukes stages of C and D tumors. The protein of p16 promoter was detected in 69% of tumor tissues. The hypermethylation of p16 gene was detected in 25% in the stages of A and B tumors. The protein of p16 promoter was detected in 81% of tumor tissues. The hpermethylation of p16 gene was detected in 100% in low differentiated carcinomas. The protein of p16 promoter was detected in 20% , the hypermethylation of p16 gene was detected in 30% , in the high and mediate differentiated carcinomas, the protein of p16 promoter was detected in 85%. Furthermore, the hypermethylation of p16 gene was detected in 63% in the lymph node metastasis and 25% in without lymph node metastasis. The protein of p16 promoter was detected in 65% in rectum and 100% in colon. Conclusions Our study demonstrated that p16 hypermethylation and protein were associated with the development of colorectal cancer and could be used as a putative prognostic indicator for this malignancy.