One case with a MLH1/PMS1 loss on IHC did not have a MLH1 mutation, but instead had a pathogenic germline variant in MSH2. The hypermethylation test later conducted on this patient’s tumor DNA turned out to be positive which indicates that her EC had a sporadic origin and was not caused by her inherited MSH2 pathogenic variant. This evidence concerns the gene MLH1 and neoplasm.