“…In most endometrial cancers with MMRd, the loss of protein function is secondary to MLH1 hypermethylation [ 11 ]. MMRd tumors are more sensitive to radiation and immunotherapy, with questionable benefit from chemotherapy [ [12] , [13] , [14] ]. The mechanisms by which MMR proteins defects determine MSI possibly differ based on whether the loss is due to MLH1 hypermethylation, somatic mutations, or germline mutations [ 15 , 16 ].…”