IDH1/2 mutations appeared more frequently in ICC (23.6%, P = 0.0002) than in GBC (4.0%) or ECC (2.3%), while ERBB2/3 mutations were found only in GBC (20.0%) and ECC (11.4%).
Specificities are observed for some alterations and anatomical subtypes: frequent fibroblast growth factor receptor 2 (FGFR2) and isocitrate dehydrogenase 1/2 (IDH1/2) alterations are specific to intrahepatic cholangiocarcinomas (ICCs), whereas frequent ERBB2 oncogene alterations are specific to extrahepatic cholangiocarcinomas (ECCs) and gallbladder carcinomas (GBCs).
The proportions of positive cases for EGFR, VEGF, and HER2 overexpression were 27.4, 53.8, and 0.9% in intrahepatic cholangiocarcinoma (IHCC), and 19.2, 59.2, and 8.5% in extrahepatic cholangiocarcinoma (EHCC), respectively.
Gene amplification and protein overexpression of HER-2/neu in human extrahepatic cholangiocarcinoma as detected by chromogenic in situ hybridization and immunohistochemistry: its prognostic implication in node-positive patients.