ERBB2 and cholangiocarcinoma: In a more recent study of surgically resected 454 CCA cases, HER2 was positive (IHC3+ or IHC2+ plus HER2 gene amplification) in approximately 14.5% of all cases, including 18.5% of dCCA, 3.0% of pCCA, 3.7% of iCCA, and 31.3% of GBC.