Mismatch repair deficiency in metastatic prostate cancer: Response to PD-1 blockade and standard therapies.

MMRd PC is associated with high Gleason score and advanced disease at presentation. Response rates to standard therapies are comparable to those reported in unselected patients and response rate to checkpoint blockade is high. Our study is limited by small sample size, and more research is needed to identify additional factors that may predict response to immunotherapy.