卵巢上皮性癌p53基因突变的检测和序列分析

Detection and Sequence Analysis of the p53 Gene Mutation in Epithelial Ovarian Cancer

目的了解卵巢上皮性癌ｐ５３基因突变的特点及其与临床分期的关系。方法采用聚合酶链反应－单链构象多态性检测（ＰＣＲ－ＳＳＣＰ）和序列分析的方法对４６例卵巢上皮性癌进行外显子５、６、７突变的检测和分析。结果ｐ５３基因突变８例并得到证实。包括８个点突变（６个错义突变，１个静息突变和１个内含子突变）和１个碱基对插入突变（在下游产生终止信号）。突变中碱基转换突变占总突变的８８．９％（８／９），并以Ｇ→Ａ的转换突变为主，占转换突变的８７．５％（７／８）。１７５、２４５位密码子的突变占总突变的６２．５％。临床Ⅰ、Ⅱ期的突变率为２０．０％，临床Ⅲ、Ⅳ期为１６．７％，差异无显著性（Ｐ＞０．０５）。结论卵巢上皮性癌ｐ５３基因突变是自发性突变，是由于ＤＮＡ合成和修复过程中的随机错误所致。１７５与２４５位密码子可能是卵巢上皮性癌ｐ５３基因突变的主要位点。ｐ５３基因突变与临床分期无关，故认为ｐ５３基因突变于卵巢癌早期就有所发生，并持续于肿瘤发展的全过程。

Objective To find thd characteristics of p53 gene mutation in epithelial ovarian cancer and to analyze the relationship between p53 mutation and FIGO stage. Methods p53 mutations in exon 5 to 7 were detected by single strand conformational polymorphism (SSCP) and sequencing technique. Results 8 of 46 tumor tissues demonstrated a SSCP band shift in the region of the gene. All of them have been characterized to represent DNA alterations by sequencing, including 8 point mutations (6 missence, 1 silent mutation and 1 in intron) and a 1 base pair insertion (introducing a stop codon downstream). Overall, 88.9% of mutation were transitions, and most of them are G→A transitions (7/8, 87.5%). 62.5% of the mutation were found in 175 and 245 codon. The percentage of the mutation in stage Ⅰ and stage Ⅱ was 20.0%, and in stage Ⅲ and stage Ⅳ was 16.7% ( P >0.05). Conclusion The arising of p53 mutations in ovarian cancer is due to spontaneous error in DNA synthesis and repair. Codon 175, 245 are the two mutational hot spots. There is no relationship between the mutation of p53 gene and FIGO stage in epithelial ovarian cancer.