Integrating morphology with molecular classification refines diagnosis and prognostication: POLEmut/MMRd subsets generally have excellent outcomes and are candidates for de-escalation or immunotherapy, whereas p53abn/high-grade tumors carry a poorer prognosis and may warrant intensified management and trials of homologous recombination deficiency (HRD)-directed strategies; routine MMR immunohistochemistry (IHC) with reflex germline testing improves Lynch detection, and future priorities include prospective validation and multi-omics to refine NSMP and identify new targets. This evidence concerns the gene MRC1 and hypoparathyroidism-retardation-dysmorphism syndrome.