RESUMO
Objectives: Immune checkpoint therapy has been promising in renal cell carcinoma, but no validated clinically relevant biomarkers exist. Metastatic deposits may have discordant biomarker expression. Methods: Fifty matched pairs of primary and metastatic kidney tumors were evaluated via immunohistochemistry for immune checkpoint proteins PD-1, PD-L1, and PD-L2 and the T-cell and macrophage surface markers CD3, FOXP3, and CD163. Semiquantitative scores incorporating prevalence of both tumor and nontumor labeling were compared between metastatic and primary kidney tumor specimens. Results: A large minority of patients had discordant expression of PD-1 (31.2%), PD-L1 (22.5%), or PD-L2 (21.5%) between primary and metastatic sites. The expression of the novel marker PD-L2 correlated with both PD-1 (r = 0.47, P = .02) and PD-L1 (r = 0.67, P < .001) in metastatic deposits. Conclusions: This study demonstrates that renal clear cell carcinoma primary tumors and metastatic deposits have some discordance in the expression of PD-L1, PD-1, and PD-L2.
