POLE and neoplasm: POLD1 alterations can also trigger accumulation of tumor mutation burden (TMB) and enhanced immune response.38,39,40,41 Previous studies showed POLE alterations are somatic while POLD1 alterations are usually germline in EC.42 While POLE alterations have been well studied as a favorable biomarker and are currently under clinical trials for identification of treatment de-escalation, the prevalence of and outcomes associated with POLD1 is unknown.