<正> Intrahepatic cholangiocarcinoma is an uncommon type of primary hepatomaand its mechanism is still unknown.Twenty samples of the cancer and the surrounding tis-sues were all taken from the Xi’an area and examined for the presence of X-gene prod-uct（HBxAg）by the avidin-biotin-peroxidase complex method.It was found that 17 cases（85%）showed positive reaction

HBxAg was present in 15 cancer samples and 16non-tumor tissue samples.This result suggests that there is a close relationshipbetween human cholangiocarcinoma and HBV

and the HBxAg might play an importantrole in the pathogenesis of cholangiocarcinoma.