Increasing tumors biomarkers are being discovered; many investigators sought to validate in human bile whether biomarkers reported for diagnosing other tumors can be used to identify CCA and benign biliary tract disease, finding that Heat shock proteins 27 (HSP27), Heat shock proteins 70 (HSP70), Pyruvate kinase M2 (PKM2), sB7-H4, 11 ligand-binding repeats (sLR11) and minichromosome maintenance protein 5 (Mcm-5), which were differentially expressed in bile of patients with CCA and benign biliary tract disease, have the possibility of diagnosis of CCA. The gene discussed is MCM5; the disease is cholangiocarcinoma.