PTEN and intrahepatic bile duct cancer: Site-specific gene abnormalities of EGFR, ERBB3, phosphatase, and tensin homolog (PTEN), ARID2, mixed-lineage leukaemia protein 2 (MLL2), MLL3, telomerase reverse transcriptase (TERT) promoter mutations were found in gallbladder cancer, PRKACA or PRKACB fusion, ELF3, ARID1B in extrahepatic bile duct cancer, and FGFR2 fusion, IDH1/2, EPHA2, and BRCA1 associated protein-1 (BAP1) in intrahepatic bile duct cancer.