MRC1 and endometrial cancer: To improve the sensitivity of detecting Lynch syndrome among endometrial cancer patients, tumour testing by microsatellite instability (MSI) and/or immunohistochemistry (IHC) analysis has been suggested for all newly diagnosed patients.2 If this analysis indicates that one or more of the MMR proteins is absent or non-functional in the tumour, the patient would be referred for further investigation and, if sporadic cancer can be excluded, offered germline DNA testing for MMR mutation(s).