Heat shock proteins 27 and 70 are potential biliary markers for the detection of cholangiocarcinoma

Abstract

Cholangiocarcinoma often is diagnosed at an advanced stage. Thus, it is necessary to establish sensitive screening methods that would allow cholangiocarcinoma and preferably its precursor lesion [biliary intraepithelial neoplasia (BilIN)] to be detected. We sought to clarify the usefulness of heat shock protein (HSP) 27 and HSP70 as biomarkers of cholangiocarcinoma and have used immunohistochemical analyses of hepatolithiatic livers to characterize HSP27 and HSP70 expression during the multistep cholangiocarcinogenesis process. HSP27 and HSP70 were measured in serum and bile samples via enzyme-linked immunosorbent assay. In hepatolithiatic tissue, the expression of HSP27 and HSP70 was increased in BilIN as well as in invasive cholangiocarcinoma. The serum levels of HSP27 and HSP70 were not significantly different between the hepatolithiatic patients with and without cholangiocarcinoma. In contrast, the bile levels of HSP27 and HSP70 were increased significantly in the patients with cholangiocarcinoma compared with those in the patients with lithiasis. Combining the measurements of the bile levels of HSP27 and HSP70 increased their usefulness as biomarkers, and the sum (HSP27 + HSP70) yielded the best sensitivity (90%) and specificity (100%). These results suggest that HSP27 and HSP70 could be used as biliary biomarkers for the detection of cholangiocarcinoma including BilIN.