AIM To establish and dharacterize a nev cholangiocarcinoma cell line from a patient living in the Opisthorchis viverrini (O. viverrini) endemic area of Northeast Thailand.METHODS: Fresh liver biopsy and bile specimens were obtained from a 65-year-old Thai woman with cholangiocarcinoma of the porta hepatis. After digestion, the cells were cultured in Hams F12 media. The established cell line was then characterized for growth kinetics, cell morphology, imm unocytochemistry and cytogenetics. Tumorigenicity of the cell line was determined by heterotransplanting in nude mice. RESULTS: The primary tumor was a poorly differentiated tubular adenocarcinoma. Examination of the bile revealed malignant cells with O. viverrini eggs. The cholangiocarcinoma cell line KKU-100 was established 4 mo after the primary culture-population doubling time was 72 h. KKU-100 possesses compact and polygonal-shapedepithelial cells. Immunocytochemically, this cell line exhibited cytokeratin, EMA, CEA, and CA125, but not α-fetoprotein (AFP), CA19-9, desmin, c-met, or p53. Such protein expressions parallel those of the primary tumor. Cytogenetic analysis identified aneuploidy karyotypes with a modal chromosome number of 78 and marked chromosomal structural changes. Inoculation of KKU-100 cells into nude mice produced a transplantable, poorly differentiated aden-ocarcinoma, similar to the original tumor.CONCLUSION: KKJ-100 is the first egg-proven, Opisthorchis- associated cholangiocarcinoma cell line, which should prove useful for further investigations of the tumor biology of this cancer.