P53 OVEREXPRESSION IN SMALL HEPATOCELLULAR CARCINOMAS CONTAINING 2 DIFFERENT HISTOLOGIC GRADES

There is evidence to suggest that a focus of less-differentiated hepat ocellular carcinoma (HCC) may arise within a pre-existing well-differe ntiated HCC, eventually replacing it. In the present study, the p53 tu mor suppressor gene was analyzed by immunohistochemistry in 31 hepatoc ellular carcinomas (HCCs) containing two or more regions in the same n odule with different histologic grades. p53 was overexpressed in the n ucleus in 13 of 31 HCCs (42%), in seven of which p53 overexpression wa s seen only in the less-differentiated area of the tumor. This suggest s that overexpression of presumed mutant p53 may have contributed to d edifferentiation during the development of HCC.