269 Background: Lymphoepithelioma-like cholangiocarcinoma (LELCC) is a rare variant of intrahepatic cholangiocarcinoma, which is highly associated with EBV infection and abundant lymphoplasmacytic cell infiltration. However, there’s limited data of genetic background in LELCC. Therefore, we want to explore the mutation profiles of LELCC, as well as copy number variations. Methods: Five patients’ tumor tissues diagnosed as LELCC, with positive EBER expression were retrospectively collected and microscopically dissected. Of them, two patients’ peripheral blood mononuclear cell served as background of germline mutations. Targeted next-generation sequencing was performed using the ACTOnco Comprehensive Cancer Panel (Ion AmpliSeq Comprehensive Cancer Panel, Life Technologies) to target all coding exons of 409 cancer-related genes for analysis of tumor tissue and blood. PDL1 immunohistochemistry staining with 22C3 antibody pharmDx was applied. Results: All EBV-associated LELCC showed positive expression of PDL1 staining, with combined positive score from 5% to 30%. Both somatic and germline mutations can be detected in LELCC tissue because diffuse infiltration of lymphocytes over tumor. After adjusting for background germline mutation frequency from peripheral blood, only mutations with allele frequency less than or around 10% were considered as somatic mutations. Overall, 10 nonsynonymous somatic mutations were detected in 4 (80%) patients with a range of 1-5 mutations per sample. Mutations were identified including BARD1, EPHA5, MUC16, TNFAIP3, CD19, PTEN, TET1, RECQL4, CD79B, and KDM5A. Copy number changes were rare in this special population. Interesting, one patient who failed to gemcitabine plus cisplatin got partial response after anti-PD1 inhibitor treatment. Conclusions: LELCC is highly correlated with PDL1 expression in tumor and immune cells. It’s necessary to have both tumor tissue and peripheral blood for next-generation sequencing to identify truly somatic mutations in LELCC.