Relationship between PD-L1 expression, CD8+ T-cell infiltration and prognosis in intrahepatic cholangiocarcinoma patients

Abstract Background Programmed death- ligand 1 (PD-L1) seems to be associated with the immune escape of tumors, and immunotherapy may be a favorable treatment for PD-L1-positive patients. We evaluated intrahepatic cholangiocarcinoma (ICC) specimens for their expression of PD-L1, infiltration of CD8+ T cells, and the relationship between these factors and patient survival. Methods In total, 69 resections of ICC were stained by immunohistochemistry for PD-L1, programmed death factor-1 (PD-1), and CD8+ T cells. CD8+ T-cell densities were analyzed both within tumors and at the tumor-stromal interface. Patient survival was predicted based on the PD-L1 status and CD8+ T-cell density. Results The expression rate of PD-L1 was 12% in cancer cells and 51% in interstitial cells. The expression rate of PD-1 was 30%, and the number of CD8+ T-cells increased with the increase of PD-L1 expression (p