Expression of Mallory bodies in hepatocellular carcinoma in man and its significance.

Evidence has been accumulating that Mallory body (MB) is a heritable phenotype of hepatocellular carcinoma (HCC) and is closely related to hepatocarcinogenesis in some carcinogen-fed animals. This prompted us to try to evaluate the MB phenomenon in human HCCs, in which its significance remains unclear to date. Whole liver slices were obtained from 28 autopsied livers in which MB-positive HCC was found, and distribution of MBs within the HCC was examined. There were three distribution patterns: clustering, diffuse, and sparse types. The clustering type was the most frequent and was found in 21 of the 28 cases. In this type, there was a formation of groups of the MB-containing cells within the HCC, and the cluster of MB-positive cells was variable in number, size, and shape. There was often a sharp border line between MB-positive clusters and the surrounding MB-negative HCC cell areas where a collision line could occasionally be seen. Some of the MB-containing HCC cells were positive for gamma-glutamyl transpeptidase and alpha-fetoprotein. These data led the authors to speculate that MB-positive HCC cells in human livers are capable of proliferation to form the clusters and that therefore, MBs are expressed as a kind of heritable phenotype in such clusters.