ABSTRACT
Background : Differential diagnoses of intrahepatic adenocarcinomas (IHAC) play an important role in the detecting primary sites and the determining type of treatment and overall prognosis of the patient. However, histopathologic findings alone have limitations of differential diagnoses of IHAC. Methods : To clarify which tumor related proteins (TRP) are useful for differential diagnoses of IHAC, TRP expression were investigated immunohistochemically, using MUC5AC, MUC2, mAb 91.9H, MUC1, and pS2, and by high iron diamine (HID) staining in 61 clinically confirmed IHACs. Results : MUC5AC (9/18, p0.05) displayed the most frequent expression in cholangiocarcinomas, and MUC2 (11/18, p0.05) was expressed more often in pancreatic adenocarcinomas than other IHAC, while MUC2 and 91.9H were not expressed at all in pancreatic adenocarcinomas. The positivity of several TRP did not correlate with tumor differentiation. Conclusions : MUC5AC, MUC2, mAb 91.9H, and HID may be useful in differentiating cholangiocarcinomas from colorectal adenocarcinomas.