Beyond Histology: A Dual-Cohort Genomic Analysis of 2901 Endometrial Carcinomas Reveals Class-Level Mismatch Repair Effects and Refines Molecular Classification.
Summary
This large genomic analysis of 2901 endometrial carcinomas refines molecular classification by addressing several clinical questions. The study confirms that all four mismatch repair genes (MLH1, MSH2, MSH6, PMS2) confer an equivalently favorable prognosis, validating dMMR status as a class-level prognostic designation. It demonstrates that the exceptional survival benefit associated with POLE-ultramutated tumors is confined to canonical exonuclease-domain hotspot mutations, excluding variants of uncertain significance. Finally, patients with TP53 mutations and high copy-number instability (CNH) are identified as having the most urgent unmet therapeutic need.
Analysis
This study is of paramount importance for clinical practice in gynecologic oncology. It provides strong evidence to refine the molecular classification of endometrial carcinoma, which will directly impact prognostic counseling and adjuvant therapy decisions. The clarification that immunotherapy eligibility based on dMMR status is independent of the specific MMR gene altered simplifies guidelines. Furthermore, distinguishing between pathogenic POLE variants and those of uncertain significance is crucial to avoid over- or under-estimating prognosis and to guide therapeutic strategies, especially for TP53-mutant/CNH patients who require innovative approaches.