Up-regulation of ninjurin expression in human hepatocellular carcinoma associated with cirrhosis and chronic viral hepatitis

The cDNA clones, which were highly expressed in liver tissues of hepatocell ular carcinoma (HCC) patients, were identified using dot hybridization and reconfirmed by Northern blot analysis. One of the clones, ninjurin (nerve i njury induced protein), showed a much higher expression level in the liver tissue of HCC patients than in normal liver tissue. Interestingly, the pres ence of ninjurin mRNA transcripts was detected with high intensity in HCC t issues when combined with viral infection and cirrhosis, but not with a nor mal liver or HCC tissue unrelated with viral infection and cirrhosis, We pr oduced a N-terminal part of recombinant ninjurin protein, as well as a mono clonal antibody specific to this polypeptide, The intensity of immunohistoc hemical staining of the liver tumor tissue, and regenerating tissue for the ninjurin protein, was stronger than that of normal liver tissue. These res ults suggest that ninjurin may play an important role in the development of HCC combined with cirrhosis and viral infection.