Background and Aims: Cholangiocarcinoma is insidious in its clinical onset, its early detection is difficult, and many patients are at an advanced stage at the time of diagnosis, thus lose the chance of radical treatment. Therefore, the search for a new biomarker for early diagnosis and prediction of treatment efficacy and prognosis of cholangiocarcinoma is of great importance. The tumor type M2 pyruvate kinase (TuM2-PK) To investigate the value of serum tumor type M2 pyruvate kinase is a tumor biomarker discovered in recent years, and may be associated with a variety of tumors. This study was conducted to investigate the change in serum TuM2-PK level in cholangiocarcinoma patients and its diagnostic value for cholangiocarcinoma.  
Methods: The serum TuM2-PK levels in 54 patients with cholangiocarcinoma, 32 patients with bile duct stones and 25 subjects undergoing health maintenance examination were compared. Using TuM2-PK>15 U/mL as the positive standard, the relations of positive rate of the serum TuM2-PK with clinical factors of the cholangiocarcinoma patients were analyzed. The diagnostic efficacy of the serum TuM2-PK level for cholangiocarcinoma was determined by using ROC curve analysis, which was compared with that of CA19-9. Finally, the pre- and postoperative changes in serum TuM2-PK level in cholangiocarcinoma patients and patients with bile duct stones as well as in cholangiocarcinoma patients undergoing radical operation or palliative operation were respectively compared.
Results: The serum TuM2-PK level in cholangiocarcinoma patients was significantly higher than that in patients with bile duct stones or healthy individuals (both P<0.05), while it showed no significant difference between the latter two groups (P>0.05). The positive rate of TuM2-PK in the cholangiocarcinoma patients was significantly associated with the degree of tumor differentiation, lymph node metastasis and clinical TNM stage (all P<0.05). The AUC value of serum TuM2-PK for diagnosis of cholangiocarcinoma was 0.781, with a sensitivity of 84.81% and a specificity of 80.00%, and the sensitivity and specificity of serum CA19-9 for diagnosis of cholangiocarcinoma were 79.63% and 84.00. The sensitivity was increased but the specificity was decreased by their combined examination. The serum TuM2-PK level was significantly reduced after surgery than that before surgery in cholangiocarcinoma patients (P<0.05), but showed no significant difference in patients with bile duct stones before and after surgery (P>0.05); in cholangiocarcinoma patients, the serum TuM2-PK level was significantly reduced after surgery than that before surgery in cases undergoing radical surgery (P<0.05), but showed no significant change in those undergoing palliative surgery before and after surgery (P>0.05).
Conclusion: The serum TuM2-PK level is increased in cholangiocarcinoma patients, and its level is closely related to the tumor progression and treatment efficacy. So, it has certain value in early diagnosis and estimation of treatment effect and prognosis for cholangiocarcinoma.