Objective To explore the expression of liver fatty acid binding protein (L-FABP) in tissues of hilar cholangiocarcinoma and the relationship between expression of L-FABP and clinicopathological factors and prognosis of the patients.Methods The retrospective case-control study was conducted.The clinicopathological data of 132 patients with hilar cholangiocarcinoma who were admitted to the Navy General Hospital between January 2003 and January 2013 were collected.The expression of L-FABP in tumor tissues and adjacent tissues of hilar cholangiocarcinoma and normal bile duct tissues were respectively detected by immunohistochemistry.Observation indicators:(1) expression of L-FABP by immunohistochemistry;(2) relationship between clinicopathological factors of patients and expression of L-FABP in tumor tissues;(3) follow-up and survival situations;(4) prognostic analysis of patients after radical resection of hilar cholangiocarcinoma.Follow-up using outpatient examination and telephone interview was performed to detect postoperative overall survival time up to June 2017.Count data were described as percentage and compared using the chi-square test.The survival time was calculated by the Kaplan-Meier method.Measurement data with skewed distribution were described as M (range).The univariate analysis and multivariate analysis were respectively done using the nonparametric test and COX regression model.Results (1) Expression of L-FABP by immunohistochemistry:the positive expressions of L-FABP were located in the cytoplasm.The low,moderate and high expression rates of L-FABP in tumor tissues were respectively 11.36％ (15/132),71.97％ (95/132) and 16.67％ (22/132),and positive-staining cells showed platy and / or diffuse distribution;the low,moderate and high expression rates of L-FABP in adjacent tissues of hilar cholangiocarcinoma were respectively 77.27％ (102/132),7.58％ (10/132) and 15.15％ (20/132),and positive-staining cells showed scattered or platy distribution,with a weaker staining intensity compared with tumor tissues;there was no positive expression in normal bile duct tissues.There was a statistically significant difference in expressions of L-FABP among tumor tissues and adjacent tissues of hilar cholangiocarcinoma and normal bile duct tissues (x2=5.423,P ＜ 0.05).(2) Relationship between clinicopathological factors of patients and expression of L-FABP in tumor tissues:cases with low,moderate and high expressions of L-FABP in tumor tissues were respectively 10,30,5 in 45 patients with tumor diameter ＜ 3 cm and 4,29,9 in 42 patients with 3 cm ≤ tumor diameter ≤ 5 cm and 1,36,8 in 45 patients with tumor diameter ＞ 5 cm,with a statistically significant difference (x2 =10.171,P＜ 0.05).(3) Follow-up and survival situations:132 patients were followed up for 5-90 months,with a median time of 33 months.During the followup,postoperative overall median survival time of 132 patients was 31 months.(4) Prognostic analysis of patients after radical resection of hilar cholangiocarcinoma:results of univariate analysis showed that tumor differentiation,lymph node metastasis and expressions of L-FABP in tumor tissues were related factors affecting prognosis of patients after radical resection of hilar cholangiocarcinoma (Z =1.845,3.156,1.243,P＜0.05).Results of multivariate analysis showed that tumor differentiation,lymph node metastasis and expressions of L-FABP in tumor tissues were independent factors affecting prognosis of patients after radical resection of hilar cholangiocarcinoma (odds ratio =0.431,1.806,3.692,95％ confidence interval:0.292-0.693,0.974-2.973,1.875-11.364,P＜0.05).Conclusions The high expression of L-FABP in tumor tissues is significantly correlated with the tumor diameter.Tumor differentiation,lymph node metastasis and expressions of L-FABP in tumor tissues are independent factors affecting prognosis of patients after radical resection of hilar cholangiocarcinoma.