ERBB2 and intrahepatic cholangiocarcinoma: Thus, we defined HER2 amplification in ICC as HER2/CEP17 ≥ 2.0 and HER2 ≥ 4.0; or HER2 mean value ≥ 6.0 in this study, which is also the interpretation criteria for HER2 fluorescence in situ hybridization (FISH) in breast cancer.