Immunohistochemical staining of PN in CCA tissues. The expression of PN was localized in fibroblasts but not cancer cells. High expression of PN was observed in well- (A), moderately- (B) and poorly-differentiated tissues (C), whereas PN negative staining CCA tissue was demonstrated (D). Benign liver tissue (E) and hepatocellular carcinoma (F) showed no to slight expression. Magnification, 100×. Double immunofluorescence staining showed co-expression of PN and α-SMA in CCA stromal fibroblasts (G). Magnification, 200×.