von Hippel-Lindau抑癌基因在散发性肾透明细胞癌中的突变及其意义

Mutation of von Hippel-Lindau tumor suppressor gene in sporadic clear renal cell carcinoma and its significance

背景与目的：von Hippel-Lindau（VHL）基因是一种抑癌基因,其突变在肾透明细胞癌的发生发展中发挥重要的作用.本研究旨在了解VHL抑癌基因在中国人散发性.肾透明细胞癌中的突变特点,并探讨基因突变与肿瘤分期、病理分级等临床病理特征的关系.方法：应用聚合酶链反应（PCR）、双向测序方法检测72例散发性肾透明细胞癌患者肾癌组织及正常肾组织中VHL抑癌基因的突变情况.结果：72例肿瘤组织中检测出VHL抑癌基因突变25例,突变率为35%.其中移码突变13例,错义突变8例,无义突变3例,同义突变l例.第1外显子6例,第2外显子5例,第3外显子12例,内含子区2例.25例突变中,6例突变位于密码子157～166区域.VHL抑癌基因突变与肿瘤分期、分级等临床病理指标无关（P＞0.05）.结论：中国人散发性肾透明细胞癌中VHL抑癌基因突变率较低,突变主要位于第3外显子,该外显子区可能存在一个突变热点区域.VHL抑癌基因突变与肿瘤分期、分级等临床病理指标无关,是肾透明细胞癌发生发展的早期遗传事件.

Background and purpose： von Hippel-Lindau （VHL） gene is one of the tumor suppressor genes and plays an important role in the carcinogenesis of clear cell renal cell carcinoma. The aim of this study was to determine the characteristics of VHL gene mutations in the sporadic clear cell renal cell carcinoma in the Chinese populations and further analyze the correlations between VHL gene mutations and clinicopathological parameters. Methods： 72 patients were enrolled in this study. The specimens of tumor and normal tissue were collected at 〈 1 hour post-operation, then immediately stored in the liquid nitrogen. The tissues were unfrozen and total genomic DNA was extracted from the samples. Different primers were designed to amplify variant exons and mutations were analyzed using double strand sequencing of VHL DNA by PCR method. Results： Mutations were detected in 25 of 72 sporadic clear cell renal cell carcinomas （35%）, including 13 frame shift mutations, 8 missense mutations, 3 nonsense mutations and 1 silent mutation. The affected sites were exon 1 in six mutations, exon 2 in five, exon 3 in twelve and intron in two. Six out of 25 mutations were in the region of codon 157- 166, where the VHL protein bound to Elongin C and Elongin B. No significant differences were observed between various pathological stages and grades. Conclusions： The percentage of VHL gene mutations was unexpectedly low in sporadic clear cell renal cell carcinoma. Mutations were mainly located in exon 3, where there might be a hot-spot mutational region. No correlations between VHL gene mutation and clinicopathological parameters were found. VHL gene mutation might be an early event in the carcinogenesis of clear cell renal cell carcinoma.