HBx gene inducing hepatocellular carcinoma in vivo and its mechanism.

Objective: To determine whether HBx gene can directly induce hepatocellular carcinoma in vivo, and to explore the mechanism of transplantation tumor in nude mice.
Methods: pCMVX/QSG7701 cell lines were vaccinated into subcutaneous tissue of nude mice. pRcCMV2/QSG7701 and QSG7701 cell lines were used as controls. The sections of transplantation tumor were observed microscopically by HE staining. RT-PCR was used to detect the expression of mutant p53 and c-Myc mRNA in transplant tumor and an other 3 cell lines.
Results: The transplant tumor occurred within the subcutaneous tissue of the nude mice inoculated with pCMVX/QSG7701 cell lines at 2nd week after the vaccination. No metastatic tumor was found in other organs. Transplant tumor was not formed in all the controls. HE staining confirmed that the transplant tumor was hepatocellular carcinoma. The mutant p53 mRNA and c-Myc mRNA expression level of transplant tumor and pCMVX/QSG7701 cells was significantly higher than that of pRcCMV2/QSG7701 and QSG7701 cells, respectively (P<0.01).
Conclusion: HBx gene can up-regulate the expression of mutant p53 and c-Myc genes, and directly induce hepatocellular carcinoma in vivo.