CD133 is one of the most important cancer-initiating (stem) cell markers and was confirmed to be expressed in solid cancers such as colon cancer. However, no one has investigated the role of CD133 in intrahepatic cholangiocarcinoma (IHCC). The aim of this study was to clarify the clinical role of CD133 expression in IHCC.

Twenty-nine patients with IHCC who underwent hepatic resection at our institution were enrolled in this study. Expression of CD133 was examined using anti-CD133 antibody. Staining was observed in the cytoplasm of cancer cells and CD133-positive cells distributed in the whole tumor. The patients were divided into two groups: the CD133-positive group (n = 14) and CD133-negative group (n = 15), in which no staining of CD133 was observed. Clinicopathological factors including hypoxia-inducible factor-1α expression were compared between the two groups. The prognostic factors were investigated by multivariate analysis using Cox’s proportional hazard model.

The 5-year survival rate in the CD133-positive group (8.0%) was worse than that in the CD133-negative group (57.0%). In the CD133-positive group, the incidence of intrahepatic metastasis and positive expression of hypoxia-inducible factor-1α tended to be higher than that in the CD133 negative group. The multivariate analysis revealed CD133 expression was an independent prognostic indicator in IHCC.

CD133 expression tended to be related to higher incidences of intrahepatic metastasis and positive expression of hypoxia-inducible factor-1α; furthermore, it was independently related to worse prognosis. Therefore, the CD133 expression is a potential prognostic indicator in IHCC.