CTCF and endometrial carcinoma: Microsatellite instability (MSI)-positive endometrioid tumours are prone to strand slippage mutations in CTCF resulting in the recurrent T204fs*18 and T204fs*26 mutations.7 We found that CTCF is genetically deleted in a further 22% of all endometrial carcinomas, and that the highest rates of CTCF genetic deletion occur in endometrial serous carcinomas (65.5%).