胃癌中p53基因失活及其蛋白产物的免疫组化分析

Study on Inactivation of p53 Gene and Immunohistochemical Analysis of p53 Protein in Gastric Cancer

应用ＰＣＲ－ＳＳＣＰ银染，Ｓｏｕｔｈｅｒｎ杂交及免疫组化等方法同步研究２５例胃癌标本的 ｐ５３基因突变，杂合性丢失及蛋白质过度表达．在２２例胃癌中同时获得有关ｐ５３基因突变和 杂合性丢失的检测结果．被检出ｐ５３基因突变的５例胃癌中，２例伴有杂合性丢失，３例仅有 ｐ５３基因突变．提示胃癌中ｐ５３基因至少有两种失活方式．１５例胃癌的ｐ５３基因突变及其过 度表达的对比分析证实了胃癌的ｐ５３蛋白质过量生成与ｐ５３基因突变密切相关．此外还发现 ３例ｐ５３蛋白过量生成的胃癌不伴有杂合性丢失，这一结果支持胃癌中ｐ５３基因存在“显性 负效应”失活方式．

Matation, loss of heterozygosity (LOH) and overexpression of p53 gene were simultaneously examined in 25 cases of gastric cancer using PCR-SSCP silver-staining, southern blot and immunohistochemistry. The results of p53 gene mutation and LOH were found in 22 cases of gastric cancer. In 5 cases of gastic cancer with p53 gene mutation, LOH was found in only 2 cases. This result indicated there were at least 2 types of inactivition of p53 in gastric cancer. Comparative analysis of p53 gene mutation and the overexpression of p53 gene in 15 cases indicated the overexpression of p53 gene was closely related with p53 gene mutation in gastric cancer. In addition, LOH was not found in 3 cases with p53 overexpression. This result supported the hypothesis that the dominant negtive effect of p53 mutant existed in gastric cancer.