ESR1 and obesity due to melanocortin 4 receptor deficiency: Indraccolo et al. studied the pathogenesis of endometrial polyps and they demonstrated a causative link: ageing, bcl-2 expression, obesity, tamoxifen regardless of timing, relationship between estrogen receptors and progestins, unbalanced estrogen therapy, estrogen-like effect, and unbalance between estrogen and progestins [10].