Decreased connexin 32 expression is associated with cellular proliferation and progression of hepatocarcinogenesis in the rat

The expression of connexin 32 (C×32), a major liver gap junction protein, during liver cell proliferation, caused by partial hepatectomy(PH), and development and progression of chemicallyinduced hepatocarcinogenesis was immunohistochemically studied in the rat. C×32 showed; 1) remarkable decrease before and during the S-phase; 2) clear decrease corresponding to increase in simultaneous expression of altered enzyme phenotypes in preneoplastic lesions; 3) Progressive decrease along with progression of hepatocarcinogenesis. Therefore, the observed decrease may indicate an important role for gap junctional intercellular communication in cell proliferation, which correlated to cellular independence and growth advantage in liver tumor progression.