PD-1 and PD-L1 Expression in Renal Cell Carcinoma with Sarcomatoid Differentiation.

Monoclonal antibodies that target the programmed death-1 (PD-1)-programmed death ligand-1 (PD-L1) axis have antitumor activity against multiple cancers. The presence of sarcomatoid differentiation in renal cell carcinoma (RCC) is associated with resistance to targeted therapy and poor responses to IL2 immunotherapy. Given the aggressive nature of RCC with sarcomatoid differentiation and the exclusion of sarcomatoid histology from metastatic RCC clinical trials, less is understood regarding selection of therapies. Here, we characterized the PD-1/PD-L1 axis in RCC with sarcomatoid differentiation. We directly compared two PD-L1 antibodies and found concordance of PD-L1 positivity in 89% of tested RCCs with sarcomatoid differentiation. Coexpression of PD-L1 on neoplastic cells and the presence of PD-1-positive tumor-infiltrating lymphocytes were identified in 50% (13 of 26) of RCCs with sarcomatoid differentiation. In contrast, only 1 of 29 clear cell RCCs (3%) had concurrent expression of PD-L1 and PD-1 (P = 0.002). Our study suggests that RCC with sarcomatoid differentiation may express PD-1/PD-L1 at a higher percentage than RCC without sarcomatoid differentiation, and patients with these tumors may be good candidates for treatment with anti-PD-1/PD-L1 therapies. ©2015 American Association for Cancer Research.