CYP19A1 and endometrial cancer: After menopause synthesis of oestrogens in non-ovarian sites such as adipose tissue predominates but expression of oestrogen biosynthetic enzymes including CYP19A1, HSD17B1 and sulphatase within endometrial cancer tissues is consistent with intracrine biosynthesis of bioactive oestrogens from blood-borne steroid precursors.