We have previously reported the cloning of cellular DNA with integrated HBV sequences from the PLC/PRF/5 cell line which derives from a human primary liver carcinoma.
Furthermore, these results indicate a differential expression of IGF-II transcripts in nonmalignant hepatocyte proliferation (benign liver tumors and cirrhosis) as compared to liver cancer.
These results indicate that tissue-specific alternative splicing of fibronectin mRNA is modified in human liver cancer and raise a possibility that the putative molecular machinery governing alternative RNA splicing of not only fibronectin but also other cellular proteins is deregulated in malignant human tumors.
Our results also suggest that deregulation of the tissue-specific alternative splicing of fibronectin pre-mRNA is not a unique phenotype of liver cancer but rather a general feature of naturally occurring human cancer.
As Senegal is a country where liver cancer incidence is one of the highest in the world and where people are highly exposed to aflatoxin, we screened 15 liver cancer samples from this country for mutation at codon 249 of the p53 gene.
Thus hepatocellular cancer tissue does not over-express mRNA for hepatocyte growth factor, though this growth factor might play a role in hyperproliferative states leading to liver cancer.
The adult FAH-/- mouse will serve as useful model for studies of the pathophysiology and treatment of hereditary tyrosinaemia type I as well as hepatic cancer.
The cyclin A gene plays an important role in both the S and G2-M phases of the cell cycle, and has been identified at a site of hepatitis B virus DNA integration in a human liver cancer.
Mutations in p53 have successfully been used to establish links between dietary aflatoxin exposure and liver cancer, exposure to ultraviolet light and skin cancer, smoking and cancers of the lung and bladder, and vinyl chloride exposure and liver cancer.
Aflatoxin may increase the proportion of p53 mutations by causing a single mutation, the codon 249 G > T transversion, thus explaining some of the excess liver cancer associated with aflatoxin exposure.
One candidate is the hepatocyte mitogen transforming growth factor alpha (TGF-alpha); in HBV-infected patients with liver cancer, TGF-alpha and HBsAg accumulate in the same hepatocytes.