The prognostic value of programmed death-ligand 1 in a Chinese cohort with clear cell renal cell carcinoma

OBJECTIVE: To investigate the association between tumor PD-L1 expression and patient survival to determine whether PD-L1 represents an independent prognostic feature for patients with nonmetastatic clear cell renal cell carcinoma. PATIENTS AND METHODS: Tissue bank of Fudan University Shanghai Cancer Center was queried to identity tissue samples of patients treated with radical nephrectomy for nonmetastatic sporadic clear cell renal cell carcinoma during the period of 2008 to 2015. Real-time polymerase chain reaction and immunohistochemistry staining was performed to detect the expression level of PD-L1 in paired cancer tissue and paracancerous tissue. RESULTS: 330 patients were enrolled into this study, with the mean age of 55.0 years at surgery and mean size of 5.2cm. 242 (73.3%) and 88 (26.7%) patients showed high and low expression of PD-L1 mRNA, respectively, while 254 patients had positive PD-L1 immunohistochemistry staining. 292 patients has consistent results for mRNA and protein of PD-L1 based upon these different detection methods. Patients with high PD-L1 expression were more likely to exhibit adverse pathologic features including advanced T stage (P=0.002) and lymph node metastasis (P=0.044). The Kaplan-Meier curves of PFS and OS stratified by PD-L1 expression had statistically significant difference. PD-L1 expression maintained a significant predictive role for PFS and OS in multivariate cox model. CONCLUSIONS: Our data suggested that PD-L1correlated with prognosis in RCC, and targeting the PD-1/PD-L1 pathway should be considered in the treatment of RCC patients.