It is reported to primarily target cholangiocytes in humans, as patients diagnosed with occupational cholangiocarcinoma had elevated levels of γ-glutamyl transpeptidase (γ-GTP) before elevation of aspartate aminotransferase (AST) or alanine aminotransferase (ALT), suggesting hepatic damage is secondary to development of cholangiocarcinoma5,10,11. The gene discussed is GPT; the disease is cholangiocarcinoma.