A systematic review with meta-analysis was performed to provide a robust estimate of the prevalence of Lynch syndrome in women with endometrial cancer, using the methodology described in our published protocol.7 The body of literature identified through this search also enabled informed discussion regarding the comparable utility of MMR immunohistochemistry (IHC), microsatellite instability (MSI), MLH1 methylation testing, and direct germline sequencing for pathological variants of the MMR genes by next-generation sequencing (NGS) for Lynch syndrome testing (eTable 2). The gene discussed is MRC1; the disease is Lynch syndrome.