GGTLC1 and diabetes mellitus: There was no significant correlation between pH and age, BMI, sex, blood group, diabetes mellitus, family history, tumor size, alkaline phosphatase, gamma-glutamyl transpeptidase, cholesterol, triglyceride, lactate dehydrogenase, total protein, albumin, white blood cells, preoperative total bilirubin, preoperative biliary drainage, ASA, TNM stage, histopathological diagnosis, or serum tumor markers.