Molecular biological study on the relationship between hepatitis B virus and hepatocellular carcinoma

本课题研究了B型肝炎病毒（HBV）DNA在不同部位肝组织和肝细胞癌（HCC）组织中的复制模式和整合模式。在一项调查中，我们分析了三个肝细胞癌结节（HCCN）的HBV DNA整合模式，在HBV感染的患者的肝脏Southern印迹杂交。结果发现，1例HCCN的HBV DNA整合模式与其他2例完全不同。我们认为，这表明不同的克隆起源，即多中心起源，在这种情况下，肝癌。我们认为这是首次在分子水平上证实肝癌的多中心起源。在接下来的研究中，我们分析了肝硬化（LC）结节中HBV DNA复制模式和整合模式的差异。在本研究中，我们发现肝细胞癌结节间的HBV DNA复制模式是异质性的。我们还发现肝细胞癌结节间的HBV DNA整合模式是异质性的，在肝细胞癌和肝细胞癌结节间没有发现共同的整合模式。这些结果表明：1）HBV DNA整合到宿主基因组中，并且相对于限制酶切割位点的整合位点在肝硬化结节（LCN）之间不同，并且可能在细胞之间不同。2)在一些LCN中，这些细胞中的一些与整合的HBV DNA克隆生长。3)LCN中HBVDNA的复制不均匀，一个小的标本如活检材料不能代表所有的病变肝区。在将活检材料解释为患者病毒复制状态的指标时，应牢记这一现象。

In this project, we analyzed hepatitis B virus (HBV) DNA replication patterns and integration patterns into the host genome among different part of the liver tissues and hepatocellular carcinoma (HCC) tissues. In one investigation, we analyzed HBV DNA integration patterns of three hepatocellular carcinoma nodules (HCCN) in the liver of a HBV infected patient by Southern blot hybridization. We found HBV DNA integration pattern of one HCCN was completely different from those of other two. We think this indicates different clonal origin, i.e. multicentric origin, of HCC in this case. We believe this is the first confirmation of multicentric origin of HCC at molecular level. In the next investigation, we analyzed the difference of HBV DNA replication patterns and integration patterns among the nodules of the liver cirrhosis (LC). In this investigation, we found the HBV DNA replication patterns are heterogeneous among the nodules of LC. We also found HBV DNA integration patterns among the nodules of LC are heterogeneous and no common integration patterns are found among the nodules of LC and HCC. These results indicate: 1) HBV DNA integrates into the host genome and integration sites relative to the restriction enzyme cutting sites are different from one liver cirrhosis nodules (LCN) to another and probably different from one cell to another. 2) In some LCN, some of these cells with integrated HBV DNA grow clonally. 3) Replication of HBV DNA is not homogeneous among LCN and one small specimen such as biopsy materials cannot represent every areas of the cirrhotic liver. This phenomenon should be kept in mind in the interpretation of the biopsy material as an indicator of virus replication state of a patient.