Given the requirement of FOXO1 for proper stromal cell decidualization and regulation of endometrial epithelial integrity along with the overlapping binding regions and in vivo regulation of PGR [53,54,55], the loss of FOXO1 in endometriosis could be partially responsible for the dysregulation of both PGR expression and downstream signaling. The gene discussed is PGR; the disease is endometriosis.