Diagnostic and prognostic value of immunohistochemical expression of S100P and IMP3 in transpapillary biliary forceps biopsy samples of extrahepatic bile duct carcinoma.

Because the biopsy specimen of extrahepatic bile duct carcinoma (EHBDC) is small and shows reactive changes, the histological distinction between malignant and benign tissue can be difficult. Recent studies reported that S100P and insulin-like growth factor II mRNA-binding protein 3 (IMP3) were not only diagnostic molecules but also prognostic biomarkers in several organs. The objective of this study is to clarify the diagnostic and prognostic value of immunohistochemical expression of S100P and IMP3 in transpapillary biliary forceps biopsy (TBFB) samples. The TBFB samples were collected from 80 patients (EHBDC, 68 patients; benign, 12 patients), retrospectively. When using cytoplasmic-positive staining for IMP3 as a marker of malignancy, the sensitivity and specificity reached 79.4 and 91.7 %, respectively. The sensitivity, specificity and accuracy achieved 89.7, 91.7 and 90.0 %, respectively, when using positive staining for IMP3 and/or positive histology as a maker of malignancy. While univariate (P = 0.033) and multivariate (P = 0.039) analysis revealed that S100P-positive EHBDC patients showed significantly shorter survival. The results of this study suggest that immunohistochemical staining for IMP3 is useful in the diagnosis of EHBDC and that of S100P is useful as a prognostic marker for EHBDC.