INS and female reproductive organ cancer: As mentioned above, specific metabolites of endogenous estrogens, the catechol estrogen-3,4-quinones, react with DNA and contribute to gynecological cancers.(67) Besides, a new effect of estrogen quinones has been noted, namely, the covalent modification of insulin by estrogen quinones reduces glucose uptake by affecting insulin signaling via insulin receptor substrate 1 phosphorylation in MCF-7 cells.(68)