DIFFERENCE IN GENE-EXPRESSION FOR MATRIX METALLOPROTEINASE-1 BETWEEN EARLY AND ADVANCED HEPATOCELLULAR CARCINOMAS

The histological observation that well-differentiated cancer cells in early hepatocellular carcinoma (HCC) invade portal tracts and/or fibro us bands and that these fibrous tissues then disappear suggests the pa rticipation of matrix metalloproteinase-1 (MMP-1) in the degradation o f fibrous tissue. To confirm this hypothesis, the authors investigated the localization of both the MMP-1 protein and its messenger RNA (mRN A) in early HCC immunohistochemically and by in situ hybridization usi ng complementary DNA (cDNA) and synthetic antisense probe of MMP-1; th ey then compared the results with those in advanced HCC. MMP-1 gene tr anscripts and protein were observed in well-differentiated cancer cell s of early HCC but not in moderately or poorly differentiated cancer c ells. Thus, cancer cells producing MMP-1 in early HCC may destroy the portal tract tissue adjacent to the cancer lesion and/or the fibrous b and of cirrhosis. These results seem to have demonstrated a difference in the mechanism of cancer growth and invasion between early and adva nced HCCs.