Currently, albeit slightly variable across regions, most national and international guidelines suggest somatic tumor testing for alterations in BRCA1, BRCA2, ATM, PALB2, FANCA, RAD51D, CHEK2 and CDK12 (homologous recombination genes) in patients with metastatic prostate cancer and for MSI-H/dMMR in patients with metastatic CRPC. The gene discussed is ATM; the disease is metastatic prostate carcinoma.