MLH1 and endometrial cancer: Two of the population-based studies of unselected endometrial cancer patients contained information relevant to the clinical validity of methylation testing for detecting sporadic tumours, but the data were incomplete.1,2,3 Lu et al. tested for MLH1 promoter hypermethylation by the MSP method in 13 patients (from their total series of 99) whose tumours were MSI-H and showed loss of MLH1 by IHC, or had uncertain IHC results.