INS and obesity due to melanocortin 4 receptor deficiency: Known risk factors for EC include increasing age, polycystic ovary syndrome (PCOS), obesity and type 2 diabetes.18, 19, 20, 21 We and others have identified altered SREBP1,11 and insulin signalling in endometrial specimens from women with PCOS or EC.10, 22 Anovulatory menstrual cycles, commonly found in PCOS women, have also been linked with EC.23 The mechanisms are thought to involve a state of progesterone deficiency.