RESUMO
Objective:To study the expression level of programmed death ligand 1 (PD-L1) in combined hepatocellular-cholangiocarcinoma (cHCC-CCA) and its correlation with the clinical characteristics and prognosis.Methods:The clinical data of 75 patients with cHCC-CCA undergoing surgery in Tianjin Medical University Cancer Institute and Hospital from January 2011 to December 2019, including 61 males and 14 females, with a median age of 55 years (36 to 77). Immunohistochemistry was conducted to determine the PD-L1 expression in tumor. The status of PD-L1 expression, clinicopathological data and prognosis of patients were analyzed.Results:In low-differentiated cHCC-CCA tissues, the proportion of PD-L1 expression (21.1%, 8/38) was higher than that in moderately to well-differentiated cHCC-CCA tissues (2.70%, 1/37, χ2=4.366, P=0.037). The median disease-free survival (DFS) and overall survival (OS)of PD-L1 positive patients were 12.3 and 15.1 months, respectively, lower than those of PD-L1 negative patients (14.4 and 23.3 months). The difference of DFS was statistically significant ( χ2=4.052, P=0.044). In multivariate analysis, major vascular invasion (DFS: HR=1.965, 95% CI: 1.119-3.450, P=0.019; OS: HR=1.781, 95% CI: 1.022-3.105, P=0.042) and lymph node metastasis (DFS: HR=2.451, 95% CI: 1.1033-5.814, P=0.042; OS: HR=2.652, 95% CI: 1.120-6.279, P=0.027) were identified as independent prognostic factors affecting DFS and OS. Conclusions:The proportion of PD-L1 positive is higher inthe low-differentiated cHCC-CCA tissue compared to that in moderately to well-differentiated cHCC-CCA. The major vascular invasion and lymph node metastasis are independent factors affecting the prognosis of patients with cHCC-CCA.