江苏省启东市乙型肝炎病毒基因型与肝癌及核心启动子突变的关系

The association of hepatitis B virus genotype and the basal core promoter mutation in Qidong, China

目的 对江苏省启东市肝癌高发区的HBV流行株进行基因型别鉴定,并分析其与肝癌的相关性. 方法自启东市肝癌高发区的182份血清标本中抽提HBV DNA,以PCR方法扩增HBV全基因或X基因,测序后与基因库中已知基因型的参照序列共同构建基因进化树,根据序列在进化树中的位置进行型别鉴定.率的比较采用χ 2检验或Fisher精确概率法. 结果对包含24例HBV携带者、11例慢性乙型肝炎患者及13例肝癌患者在内的48例患者的血清HBV全基因测序结果显示,44例（91.7%）为C2基因型,4例（8.3%）为B2基因型,未见A、D、E、F、G、H等型别,也未见B/C重组病毒.以X基因测序方法对182例患者血清标本的鉴定结果显示,C2和B2型分别占92.9%（169例）和5.5%（10例）,另有1.6%（3例）为B2/C2混合感染.启东地区C基因型的感染率明显高于邻近上海地区的78.9%（χ2=12.252,P〈0.01）.在81例肝癌和77例肝炎患者中,B、C基因型HBV的分布差异并无统计学意义（P〉0.05）.核心启动子区T1762/A1764联合突变在C基因型中的发生率为70.3%,明显高于B基因型中的30.8%（P〈0.05）;T1766和A1768突变则仅见于C基因型病毒中. 结论启东地区HBV感染以C2基因型为主,但其与肝癌的发生未见明显相关性.C基因型中较易出现核心启动子突变.

Objective To investigate the prevalence of hepatitis B virus （HBV） genotypes and the association with hepatocellular carcinoma （HCC） or basal core promoter （BCP） mutation in Qidong, China.Methods The whole genome of HBV or X gene sequences were obtained from serum samples of HBV infected patients by using PCR and direct sequencing methods. Phylogenetic tree was constructed to determine the genotypes or subgenotypes of HBV. Results According to the phylogenetic tree constructed from full-length sequence of HBV, genotype C2 was predominant in Qidong area. It was prevalent in 44 out of the 48 cases （91.7%）, whereas genotype B2 only existed in 4 cases （8.3%）. No other genotypes or recombinant types were found in Qidong patients. The result of genotyping based on X gene sequence confirmed the above observation. In a total of 182 samples, 169 （92.9%） showed genotype C2 and 10 （5.5%） showed genotype B2. There were 3 （1.6%） patients showed a coinfection with C2 and B2. The infection rate of genotype C in Qidong was significantly higher than that in neighboring city Shanghai （ χ2= 12.252, P 〈 0.01）. There was no significant difference of genotype distribution between HCC and chronic hepatitis groups （P 〉 0.05）. The frequency of T1762/A1764 double mutation in genotype C2 （70.3%） was significantly higher than that ingenotype B2（30.8%.P〈0.05）.The other two types of point mutation which also occurred in BCP,i.e.T1766 and A1768,were only seen in genotype C2.Conclusions （1）Genotype C2 is the predominant genotype in Qidong,China.（2）There is no association between genotype C and HCC in Qidong.（3）Genotype C has a higher prevalence of BCP mutation than genotype B.