GGTLC1 and digestive system neoplasm: The role of carcinoembryonic antigen (CEA), gamma glutamyl transpeptidase (gamma GT), phosphohexose isomerase (PHI), pseudouridine (psi) and acute phase reactant proteins (C-reactive protein (CRP) alpha 1-antichymotrypsin (ACT) and alpha 1-acid glycoprotein (AGP] in assessing the prognosis of gastrointestinal neoplasms and the discriminant function in distinguishing benign from malignant diseases of the GI tract was examined.