O’Brien et al. described a mosaic MSH2 PV in a patient with endometrial adenocarcinoma and keratoacanthomas (KA); the diagnosis was confirmed through deep tumor sequencing and reanalysis of blood-derived DNA, following IHC that revealed loss of MSH2 and MSH6 expression in both tumors [55]. The gene discussed is MSH2; the disease is endometrium adenocarcinoma.