Approximately 2-4% of endometrial cancer (10% in women diagnosed under the age of 50) is attributable to Lynch syndrome,1,2,3,4 an autosomal dominant cancer-prone syndrome caused by germline mutations in the MLH1, MSH2, MSH6 or PMS2 genes, which encode components of the DNA mismatch repair (MMR) pathway, or, in a small proportion of cases, by deletions in the EPCAM gene that lead to epigenetic silencing of the adjacent MSH2 gene (reviewed in 5). This evidence concerns the gene MSH2 and endometrial cancer.