MSH6 and cancer: The most frequently mutated genes with known relevance to cancer were TP53 (39/39 cases, 100%), BRCA1 and BRCA2 (15/39 including five germline, 38%), DDR genes MLH3, MSH2, MSH6, and RAD51B (8/39, 21%, none hypermutant), PIK3CA (5/39 all missense hotspot mutations, 13%), MGA (4/39, 10%), CSMD3 (3/39, 8%), NF1 (3/39, 2 frameshift, 8%), AURKA (2/39, 5%), and CNTRL (2/39, 5%).