MSH2 and neoplasm: NGS using the FoundationOne CDx panel showed a tumor mutational burden (TMB) of 10 muts/Mb, microsatellite stable status, BRCA2 deletion, CBL mutation, TMPRSS2-ERG fusion, MYC gain, and RAD21 gain, and no alteration of MSH2. Given BRCA2 loss, the patient was treated with the PARP inhibitor olaparib, which resulted in a 63% decline in his PSA over 6 months from 677 ng/ml to a nadir of 251 ng/ml (Fig. 1A), near-resolution of his liver metastases (Fig. 1C), healthy weight gain, and restoration of his physical function.