E. De Marzio

Antibodies to hepatitis C virus in patients with hepatocellular carcinoma

To study the potential relationship between the hepatitis C virus (HCV), the major etiologic agent of parenterally transmitted non-A, non-B hepatitis, and the development of hepatocellular carcinoma (HCC), we tested the presence of anti-HCV antibodies in sera from a large panel of HCC patients of different racial and geographical origins. Anti-HCV antibodies were detected in 82 out of 114 (71.9%) HBsAg-negative HCC patients and in 15 out of 53 (28.3%) HBsAg-positive patients. No significant difference in the prevalence of anti-HCV antibodies was found in the HBsAg-negative HCC patients when they were divided according to presence of anti-HBs and/or anti-HBc antibodies, or absence of all hepatitis B virus (HBV) serological markers. The prevalence of anti-HCV antibodies was similar in HCC patients of Caucasian and African origin. No differences were noted when the patients were grouped according to sex. The mechanisms by which HCV might contribute to the development of HCC need to be further investigated. As for HBV infection, the necro-inflammation associated with HCV infection may induce cirrhosis, regeneration and eventually malignant transformation. The finding that few anti-HCV patients had HCC which is not superimposed on cirrhosis suggests that HCV could, however, exert some direct effect on the development of HCC.

The hepatitis B virus X protein transactivation of c-fos and c-myc proto-oncogenes is mediated by multiple transcription factors.

We have constructed two expression vectors in order to study the action of the HBV 17 Kd X protein on the c-fos and c-myc promoters. The results show that the promoters contain multiple elements that respond to X protein, suggesting involvement of multiple transcription factors. The exact mechanism of the interaction remains elusive, but our data allow speculation about the factors that may be influenced.

Truncated pre-S/S proteins transactivate multiple target sequences

In order to investigate the transactivational function of HBV truncated preS/S proteins we have constructed two sets of plasmids and have tested their transactivational potential on the c-myc regulatory sequences and the TPA-responsive element. We found that preS/S proteins only become transactivationally active when truncated at the carboxy terminal end. Furthermore, using immunofluorescence microscopy we determined that the proteins are located exclusively in the cytoplasm, apparently ruling out DNA binding and activation of factors in the nucleus.

Recombinant immunoblot assay for hepatitis C virus antibody in chronic hepatitis.

Testing for hepatitis C virus by ELISA requires confirmation by recombinant immunoblot assay (RIBA). The first-generation RIBA uses the same antigen as used in the ELISA and one further antigen. A second-generation RIBA in which two further antigens are present, detects positivity that is not found by either the ELISA or the original RIBA. Consequently, although it is adequate to test ELISA positive sera with the first-generation RIBA, the second-generation assay is recommended for confirming negativity.