A human hepatic adenosquamous carcinoma cell line (KMC-2) was established from a serially transplanted tumor in nude mice (nuKMC-2), which originated from human cholangio-cellular carcinoma and showed histological alteration from adenocarcinoma to squamous cell carcinoma (SCC) along with serial transplantation. KMC-2 cells in monolayer culture proliferated in a sheet-like arrangement with a population doubling time of 29.5 h, whereas the cells in 0.1% collagen gel embedded culture formed a compact and tubular structure with the population doubling time of 35.4 h. The cells secreted carbohydrate antigen 19-9 (CA19-9), tissue polypeptide antigen and SCC-related antigen. The back-transplanted nude mouse tumor exhibited morphologic features of adenosquamous carcinoma resembling those in the original nude mouse tumor. IFN-alpha, IFN-gamma and TNF-alpha suppressed cell proliferation significantly. Functionally, IFN-gamma significantly suppressed CA19-9 secretion, and conversely promoted SCC-related antigen secretion. These findings suggest that KMC-2 is the first human hepatic adenosquamous carcinoma cell line primarily originated from adenocarcinoma; the environmental factors, such as the presence of extracellular matrix and the cytokines influenced the growth, morphology and function of KMC-2.