In patients with multiple primary cancers, pathogenic variants were most commonly identified in BRCA1 (38.5%), BRCA2 (17.9%), and the mismatch repair genes – MLH1, MSH2, MSH6 (20.5%), while 23.1% of pathogenic mutations were in other moderate- to high-penetrance cancer predisposition genes. The gene discussed is MLH1; the disease is cancer.