Previous studies have shown that colorectal and endometrial tumors carrying mutations in POLE exonuclease domain (ExoD) and in POLD1 exhibit a high burden of mutations, are typically MSS but few cases with microsatellite instability (MSI) have been reported, and do not exhibit loss of heterozygosity (LOH) [20, 38–46]. Here, POLD1 is linked to endometrium neoplasm.