ERBB2 and neoplasm: The most common primary tumour location was the gallbladder (N = 3, 42.9%) and extrahepatic bile duct (N = 3, 42.9%) in the HER2-positive group, while gallbladder (N = 14, 41.2%) and intrahepatic bile duct cancer (N = 12, 35.3%) were predominant in the HER2-negative group.