Molecular biological analysis of a development and progression of hepatocellular carcinoma to establish a rational treatment for it

我们的实验目标是(1)对肝细胞癌（HCC）的发生和进展进行分子生物学分析，(2)建立一种分子生物学诊断方法来区分多中心发展和肝内转移。作为多发性HCC的鉴别诊断，乙型肝炎病毒DNA （HBvDNA）在肿瘤中的整合模式是可用的，即在多中心HCC的情况下，HBvDNA在每个肿瘤中的整合模式是不同的。但在日本，HCC患者合并HB病毒感染的比例不到30%。因此，对其他HCC特异性癌基因的p53抑制癌基因突变模式的分析应从现在开始。然而，由于我们无法从人类病例中获得早期或癌前病变的病例，因此很难分析人类HCC的发生和进展。因此，在本学期内，我们开发了一种由DirDirect Deep Black Extra (DDB-Ex)（一种联苯胺色素）诱导的小鼠实验性HCC模型。在组织学上，这种模式下的肿瘤与人类HCC非常相似，即肿瘤是结节状的，在组织学上生长在不同厚度的索中，这与人类小梁型HCC相同。在分子生物学研究中未发现p53抑制基因突变，但在该模型中检测到65%的Ha-ras癌基因突变和12%的Ki-ras癌基因突变。DDB-Ex诱导小鼠肝细胞癌具有与人肝细胞癌相同的病理和分子生物学特征，可为研究人肝细胞癌的发生发展提供依据。

Our experimental goal are (1) molecular biological analysis of development and progression of hepatocellular carcinoma (HCC) and (2) establishment of a molecular biological diagnostic method to differentiate multicentric development from intrahepatic metastasis of HCC.As differentiated diagnosis of multiple HCC,integration pattern of hepatitis B viral DNA (HBvDNA) in the tumor was availabel, that is in case of multicentric HCC,integration pattern of HBvDNA is different in each tumor. But, HCC patients with HB viral infection were less than 30% in Japan. So, analysis of mutation pattern of p53 supressor oncogene of other HCC specific oncogene should be available from now. While as analysis of development and progression of HCC in human was difficult, because we could not get such a case as in early stage or in precancerous lesion from human cases. So, within this term, we developed an experimental HCC model in mice induced by DirDirect Deep Black Extra (DDB-Ex), a pigment of the Benzidine. Histologically the tumors in this mode were very similar to those of human HCC,that is the tumor is nodular and histologically grow in cords of variable thickness which is same as the human trabecular pattern HCC.In molecular biological study no mutations in the p53 supressor gene were found out but 65% mutations in the Ha-ras oncogene and 12% of mutations in Ki-ras oncogene were detected in this model. The HCC in mice induced by DDB-Ex share the pathological and molecular biological character with human HCC and is available for studying the development and progression of humanHCC.