Transurethral resection of prostate (Specimen 1) revealed high-grade prostate adenocarcinoma (Gleason 5 + 4 = 9) with genomic deletion of MSH2 by next generation sequencing (NGS) and loss of MSH2 and its binding partner MSH6 protein expression by immunohistochemistry (IHC), consistent with MMRd PCa. Here, MSH6 is linked to prostate adenocarcinoma.