ESR2 and endometriosis: IGF‐I may contribute to endometriosis development via upregulation of oestrogen receptor beta (ERβ) and aromatase expression through IGF‐1R/ phosphatidylinositol 3‐kinase (PI3K)/AKT pathway57 so that inhibitors of this signalling pathway can suppress the development of endometriosis by downregulating the expression of pro‐inflammatory cytokines and proteolytic factors.58