Clinicopathological and Prognostic Significance of Immunoscore and PD-L1 in Intrahepatic Cholangiocarcinoma

BACKGROUND: An increasing amount of evidence reveals that immunosuppression is a major issue in cancer progression. The association of immunoscore (IS) and its impact on clinical outcome have been studied in many tumor types, but its significance in intrahepatic cholangiocarcinoma (ICC) is poorly known. METHODS: By immunohistochemistry, CD3 and CD8 expressions were assessed in tissue samples of 50 cases of postoperative ICC. The IS was determined by analyzing CD3+ and CD8+ expression data in different areas (intratumor and invasion margins). The relationship between IS and clinicopathological characteristics, including the overall survival (OS) and recurrence-free survival (RFS), was analyzed. In addition, PD-L1, a major regulator of immune escape, was also assessed in tumor cells by immunohistochemistry. RESULTS: IS was related to histological differentiation (P=0.026), the presence of lymphoid metastasis (P=0.034), and TNM clinical stages (P = 0.031) of ICC. High IS was significantly associated with better RFS (P=0.033) and OS (P=0.014). IS was an independent prognostic factor for better OS in multivariate analysis. PD-L1 expression was closely related to tumor vascular invasion (P=0.044). Although there was no association between PD-L1 expression and IS, high PD-L1 expression in tumor cells indicated poor RFS (P=0.017) and OS (P=0.004) in ICC. CONCLUSION: The IS and PD-L1 may be used as a complement to the TNM system for predicting the prognosis of patients with ICC.