EXPRESSION OF GAP JUNCTION PROTEIN CONNEXIN-32 AND E-CADHERIN IN HUMAN HEPATOCELLULAR-CARCINOMA

The expression of connexin 32, a major gap junction protein, and E-cad herin, an intercellular adhesion molecule that is supposed to be invol ved in the regulation of gap junctional intercellular communications, was examined immunohistochemically in seven specimens of human hepatoc ellular carcinoma and surrounding non-carcinomatous tissues. We found that the number of connexin 32-positive spots per mm(2) was significan tly less in hepatocellular carcinoma tissues than in the surrounding n on-carcinomatous cirrhotic tissues (4360+/-3390/mm(2) vs 10 030+/-3690 /mm(2); p<0.01). The number in the latter was also significantly less than that in normal controls (23 560+/-4170/mm(2)). E-cadherin was exp ressed in all non-carcinomatous hepatocytes as well as carcinomatous c ells, except for one case of Edmondson's grade III hepatocellular carc inoma. These results suggest an impairment of cell-to-cell communicati ons in human hepatocellular carcinomas.