GPT and cholangiocarcinoma: However, a significant difference was found in levels alanine aminotransferase (ALT), and alanine aminotransferase (AST), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), total bilirubin (TBIL), direct bilirubin (DBIL), Urea, AFP, CEA and CA-199 between Control and CCA samples.