燃煤型砷中毒患者p16基因缺失及启动区CpG岛甲基化的观察

目的检测燃煤型砷中毒(地砷病)患者p16基因缺失及启动区甲基化的变异,探讨p16基因异常改变在地砷病发生发展乃至癌变过程中的作用。方法采用多重PCR法对103例砷中毒患者和110例正常对照人群p16基因第1、第2外显子缺失情况进行检测;同时采用甲基化特异性PCR法(MSP)和PCR产物测序技术对95例砷中毒患者和100例正常对照人群p16基因启动区甲基化情况进行分析。结果(1)正常对照组p16基因缺失率为5．45％;病例组为14．56％,以第2外显子缺失为主,其中轻、中、重度中毒组p16基因缺失率分别为9．09％、12．50％和19．51％;非癌变组和癌变组p16基因缺失率分别为8．70％和38．89％。以上差异有统计学意义(P<0．05或P<0．01)。(2)对照组p16基因甲基化阳性率为2．00％;病例组为42．11％,其中轻、中、重度中毒组p16基因甲基化阳性率分别为26．32％、41．67％和50．00％;非癌变组和癌变组阳性率分别为21．74％和55．56％。以上差异均有统计学意义(P<0．05或P<0．01)。结论p16基因缺失及启动区甲基化在地砷病的发生发展乃至癌变过程中起重要作用。

Study on p16 gene deletion and promoter 5' CpG island hypomethylation in coal-burning arsenism patients

Objective To detect the situation of p16 gene deletion and hypermethylation of promoter 5' CpG island in coal-burning arsenism patients and to analyze the role of the aberrant change of p16 gene in the genesis and development, even carcinogenesis in endemic arsenism. Methods Multi-PCR and methylation-specific polymerase chain reaction (MSP) were respectively performed to analyze p16 exon1 and exon2 deletion and hypermethylation of promoter CpG island in arsenism patient group and control group. Simultaneously, PCR products were sequenced to analyze some positive and negative products of MSP. Results (1 )The rate of p16 gene deletion was 5.45% and 14.56% in control group and patients group respectively. The deletion occurred mainly in exon 2. And the deletion rate was respectively 9.09%, 12.50% and 19.51% in mild, moderate and severe arsenism groups. Meanwhile, the deletion rate was 8.70% and 38.89% in non-carcinoma group and carcinoma group, respectively. The variance had statistical significance (P < 0.05 or P < 0.01). (2)The positive rate of p16 gene promoter CpG island hyermethylation was 42.1% and 2.0% in case group and control group, respectively; it was 26.32%, 41.67% and 50.00% in mild, moderate and severe arsenism groups, and 21.74% and 55.56% in non carcinoma group and carcinoma group, respectively. The differences were statistically significant (P < 0.05 or P < 0.01). Conclusions Deletion and hypomethylation of p16 gene may play an important role in the genesis and development, even carcinogenesis of endemic arsenism.