Objective:  To investigate the expression of SUMO-activating enzyme subunit 2 (SAE2) in cholangiocarcinoma tissue and its clinical significance. 
Methods: The expressions of SAE2 in 60 specimens of cholangiocarcinoma tissue and 20 specimens of normal bile duct tissue were detected by immunohistochemical staining. The relations of SAE2 expression with the clinicopathologic factors and prognosis of the patients were analyzed.
Results: The positive SAE2 expression rate in cholangiocarcinoma tissue was significantly higher than that in normal bile duct tissue (71.67% vs. 30.00%, χ2=10.972, P<0.001). The SAE2 expression was significantly associated with the degree of pathological differentiation of the tumor and TNM stage of the patients (both P<0.05). The median survival time of patients with positive SAE2 expression was significantly shorter than that of patients with negative SAE2 expression (13.0 months vs. 30.7 months, χ2=13.805, P<0.001). Results of univariate analysis showed that the SAE2 expression and TNM stage were significantly relevant to the prognosis of the patients (both P<0.001), and the results of Cox multivariate regression analysis identified that the SAE2 expression and TNM stage were independent factors for the prognostic of patients (all P<0.01).
Conclusion: The expression of SAE2 is increased in cholangiocarcinoma tissue, and it is related to the poor prognosis of cholangiocarcinoma patients, suggesting SAE2 expression may be involved in the occurrence and development of cholangiocarcinoma.