不同时期胃癌中p16基因缺失和突变的研究

Deletion and Mutation of p16/mts1 Gene in Human Gastric Cancer of Different Periods

目的 探讨p16基因纯和缺失和突变与胃癌发生的关系。方法 采用PCR、多重PCR、PCR SSCP和DNA测序技术分析 5 0例胃癌组织中p16基因的表达情况 ,其中早期胃癌 7例 ,进展期胃癌 43例。结果 p16基因总的点突变频率为 8.0 0 % (4 5 0 ) ,早期胃癌为 14 .2 9% (1 7) ,进展期胃癌为 6.98% (3 4 3 ) ,两者比较差异无显著性意义 (P>0 .0 5 ) ;p16基因突变与肿瘤的大小、位置、分化程度和有无淋巴结转移无关 (P>0 .0 5 )。p16基因总的纯和缺失频率为 16.0 0 % (8 5 0 ) ,早期胃癌为 0 (0 7) ,进展期胃癌为 18.60 % (8 4 3 ) ,两者比较差异有显著性意义 (P<0 .0 5 ) ;p16基因缺失频率与肿瘤分化程度和有无淋巴结转移有关 (P<0 .0 5 )。结论 p16基因点突变是胃癌发生的早期事件 ,对胃癌早期诊断有一定帮助 ;p16基因纯和缺失是胃癌的晚期事件 ,可能与胃癌的转移和复发有关。

Objective To determine the frequency and type of p16 gene homozygous deletion and mutation with the progression of human gastric carcinogenesis.Methods PCR (polymerase chain reaction),SSCP (single strand conformation polymorphism) and DNA sequencing were performed on 50 operative tissues, which included 7 early gastric cancer and 43 advanced gastric cancer. In this group there were 36 male and 14 female patients aged 35 to 68,which included 30 well differetiated adenocarcinoma and 20 poor differentiated carcinoma; 19 patients with lymph node metastases.Results Total mutation frequency of p16 gene was 8.00%(4/50), including 14.29%(1/7) of early cancer and 7.00%(3/43) of advanced cancer,there was no significant difference between early and advanced cancer ( P >0.05). In addition, p16 gene mutation was not related to site,location,grade of tumor differentiation and lymph node metastases, respectively. Total deletion frequency of p16 gene was 16.00%(8/50), of which 18.60%(8/43) was detected in advanced cancer, but no cases in early cancers. There was a significant difference between early and advanced cancer ( P <0.05), and frequency p16 gene homozygous deletion was related to grade of tumor differentiation and lymph node metastases, respectively. Direct DNA sequencing displayed that 4 point mutations detected in 99,125,433,441 base, there were 3 missense mutation and 1 same sense mutation, no deletion or insertion was found. Conclusion p16 gene mutation is an early event in gastric carcinogenesis,it helps early diagnosis of human gastric carcinoma. p16 gene homozygous deletion is a late event in gastric carcinogenesis,it might relate to metastases and recurrence of gastric cancer.