Due to the fact that women with unexplained infertility show reduced expression of H19 in the eutopic endometrium, H19 regulates let-7 and let-7 targets IGF1R, and it is useful to determine the role of H19 in the endometrium and its relationship to IGF signaling in endometriosis [54,55]. The gene discussed is H19; the disease is endometriosis.