CCD44, a transmembrane
glycoprotein receptor, plays significant roles in cell migration, differentiation, and survival signaling which are important for both normal and
cancer cells. In this study, we examined the expression of all
isoforms of CD44 by immunohistochemistry in 3 cases of biliary
cystadenoma, 15 cases of non-invasive
cystadenocarcinoma (CAC) bile duct
tumors, and 67 cases of the aggressive bile duct
tumor,
cholangiocarcinoma (CCA). Normal bile duct epithelia at different segments along the biliary tree did not express CD44. However, normal biliary cells of the large bile duct adjacent to
tumor areas and dysplastic biliary cells in CCA tissues were positive. CD44 was not expressed in
cystadenomas and the majority of CACs. Two CAC cases with short survival and the majority of CCA aberrantly expressed CD44. These observations suggest important roles for CD44 in the early stage of
carcinogenesis and progression of
bile duct cancer. Regardless of the type of bile duct
tumor, CAC or CCA patients with positive CD44 expression in biliary epithelia had significant shorter survival than those with negative CD44. Aberrant expression of CD44 in CAC or CCA tissues may indicate an unfavorable patient outcome and may serve as a useful practical adjunct to conventional prognostic indicators for
bile duct cancer.