Abstract: 【Objectives】 To investigate the expression and clinical significance of pyruvate kinase M2 (PKM2) in intrahepatic cholangiocarcinoma (ICC). 【Methods】 A total of 86 ICC patients who underwent surgical treatment between January 2008 and September 2010 were involved in this study. The expression of PKM2 in 86 pairs of ICC tissues and adjacent non-carcinomous tissues was detected by immunohistochemistry. Then the correlation between the expression of PKM2 and the clinicopathological characteristics of ICC patients was analyzed by statistical methods. Kaplan-Meier survival analysis was performed to evaluate the prognostic factors in ICC patients. 【Results】 The expression of PKM2 in ICC tissues was significantly higher than that in adjacent non-carcinomous tissues (P < 0.001). PKM2 levels were significantly higher in ICC cases with lymphatic metastasis than that without lymphatic metastasis (P < 0.001)

likewise in poorly differentiated adenocarcinomas than that in well and moderately differentiated adenocarcinomas (P = 0.048). PKM2 expression in ICC patients without distant metastasis was significantly lower than that in patients with distant metastasis (P = 0.002). PKM2 expression in ICC patients with clinical stage Ⅳ was significantly higher than that in the patients with clinical stage Ⅰ

Ⅱ and Ⅲ (P = 0.006). PKM2 levels were also significantly higher in ICC cases with perineural invasion than that without perineural invasion (P = 0.024). The 5-years overall survival rate in high PKM2 expression group (0%) was significantly lower than that in low PKM2 expression group (15%) of ICC patients (P < 0.001). Univariate and multivariate analysis demonstrated that PKM2 expression (P < 0.001) and perineural invasion (P = 0.012) were adverse significant prognostic factors for ICC patients.【Conclusions】 PKM2 high expression was associated with malignant characteristics of ICC. PKM2 could be used as an independent prognostic factor for ICC patients