四川地区宫颈癌组织HPV18和HPV45 E6基因突变分析

Analysis of E6 Variants of Human Papillomavirus Type 18,45 Isolated from Cervical Cancer Patients in Sichuan Province

采用聚合酶链反应技术对四川地区2003～2004年收集的60例宫颈癌患者的癌组织DNA进行人乳头瘤病毒（HPV）E6基因扩增，获得HPV18和45型E6基因．序列分析发现，18型三例E6基因有同样的两处同义突变；45型两例E6基因发生突变，一例有两处碱基突变，另一例发生六处碱基突变，其中两处涉及氨基酸变化，均位于E6抗原决定簇区．HPV45型E6基因中134位c→t，157位c→t，259位g→t和341位t→c的碱基点突变未见报道．另外，该地区HPV18和45型突变株之间存在碱基互变，它们之间的最小差异比野生型HPV18和HPV45之间的差异小4．05％，该数值比在非洲发现的突变株的要小很多，该结果支持HPV18和HPV45可能起源于非洲的观点．

The E6 genes of human papillomavirus（HPV） 18 and 45 variants were isolated and amplified by PCR from the tumor tissues of patients with cervical cancer in Sichuan Province of China, and the E6 genes were sequenced for investigating their structural characteristics and variability. The same two point silence mutations were found in three samples of HPV18, and six point mutations were found in one sample of HPV45, resulting in changes of the translated amino acids at two points（T19I and C53F） which are located in the HPV E6 epitope regions. Some point mutations of the HPV45 are identical to those nucleotides found specifically in the HPV18 from these samples, the diversity between HPV18 and HPV45 of Sichuan variants is less by 4. 05% than between HPV18 and HPV45 of wild types, this value is lower than that of variants isolated from Africa, which support the hypothesis that the phylogenetic root of HPV18 and 45 is in Africa.