宫颈癌组织中HPV16E7序列多态性分析

Sequence polymorphism of human papillomavirus type 16 E7 in cervical cancer

目的探讨广东地区宫颈癌组织中HPV16肿瘤相关性抗原E7基因序列的多态性。方法采用通用引物PCR直接测序法对宫颈癌标本中的HPV分型,从含有HPV16型的标本中采用自行设计的多重引物通过巢式PCR扩增出HPV16E7,经DNA序列测定法检测其基因变异,进而寻找其热点突变。结果50例宫颈癌组织HPV-DNA的检出率为78%,其中HPV16和HPV18型混合感染18例,单纯HPV16型感染15例。33例含有HPV16型的标本中扩增出25例HPV16E7,其中17例647位核苷酸“T”变异“C”,导致相应的蛋白质由天冬氨酸变异为丝氨酸。结论广东地区宫颈癌组织中HPV16E7DNA序列发生碱基替换的区域主要在647位至846位,热点突变点为Nt647和Nt846。

Objective To explore the genetic polymorphism of E7 open-reading frame of human papillomavirus （HPV） type 16 in cervical cancer. Methods The types of HPV was identified by sequence analysis of the PCR product of HPV in cervical cancer tissues. HPV 16 gene fragment in the cervical cancer tissue was amplified by HPV-specific PCR with general consensus primers, Results The positivity rate of high-risk HPV types in 50 cases of cervical cancers was 78%. Mixed infection of HPV16 and HPV18 was found in 18 cases, and the infection with HPV16 alone occurred in 15 cases. HPV16 E7 was amplified from 25 out of the 34 cases positive for HPV16. A T-to- C change occurred in the 647th nucleotide in the viral nucleotide sequence, causing conversion of the Asn codon of E7 gene into a Ser codon. Conclusions The most frequently observed substitution in HPV 16 E7 open reading frame occurs in the discrete regions of 647-846, and some substitutions result in the same-sense mutation. The hot-spot mutation of HPV 16 E7 in cervical cancers in Guangdong Province occurs at the nucleotide 647 and 846 in the DNA sequence.