In particular, women diagnosed with non-endometrioid tumours who have survived without recurrence from this earlier era may harbour a constitutional MMR pathogenic variant, as survival in LS is known to be good, and tumours may on review be reclassified with modern pathology.15 Second, we provide detailed clinical annotation for all proven LS-associated ovarian tumours as well as comprehensive molecular phenotyping, including MMR, MSI and, where indicated, MLH-1 promoter methylation status. This evidence concerns the gene MLH1 and neoplasm.