In view of the emerging connection between the insulin/IGF system, obesity and diabetes with endometrial cancer etiology and progression, and given our recent identification of the ZYG11A gene as a candidate downstream target for IGF1 action, we investigated in this paper the regulation and action of ZYG11A in endometrial cancer cell lines. Here, ZYG11A is linked to obesity due to melanocortin 4 receptor deficiency.