Fig. 2From: Prognostic value of functional SMAD4 localization in extrahepatic bile duct cancerThe definition of tumor invasion front and tumor central lesion, and typical immunohistochemical labeling for SMAD4 in extrahepatic biliary tract cancer. a The definition of tumor invasion front and tumor central lesion. Scale bar = 500 µm, × 20 magnification. b–e Typical immunohistochemical labeling for SMAD4 in extrahepatic biliary tract cancer. Scale bar = 50 µm, × 400 magnification. b Nuclear SMAD4 expression is negative, score = 0. c The percentage of nuclear positive SMAD4 is 0–25%, score = 1. d The percentage of nuclear positive SMAD4 is 25–50%, score = 2. e The percentage of nuclear positive SMAD4 is above 50%, score = 3Back to article page