ESR1 and brain aneurysm: Subtypes of estrogen receptors and their signaling mechanisms identified in HCVECs could be applicable for developing estrogen-like compounds to specifically bind to a subtype of estrogen receptors with greater specific action on the cerebral arteries, without the estrogen-dependent side effects on the reproductive organs, to prevent cerebral aneurysm formation in menopausal and postmenopausal woman.