Of 11 tested patients, a KRAS mutation was detected in the tumor of two patients with cholangiocarcinoma, one in codon 12 and another in codon 13.[15] A third patient's gallbladder carcinoma demonstrated FISH amplification of HER-2/neu (HER-2/neu: CEP17 signal ratio: 6.49). Here, ERBB2 is linked to cholangiocarcinoma.