Steroidogenic expression of delta 5-3 beta-hydroxy pathway of androgen biosynthesis by human breast carcinoma

In order to determine whether human mammary tumours could contribute to cholesterol and dehydroepiandrosterone biosynthesis in breast cancer patients, incubations of homogenates of infiltrating ductal carcinoma were carried out separately with 2-14C acetate (patient, n = 6; 21-80 years) and 7n-3H pregnenolone (patient, n = 5, 36-74 years) as substrates. With the aid of the reverse-isotope dilution technique, 14C cholesterol and 3H dehydroepiandrosterone were characterized; these two gave maximum yields of 2.38 X 10(-4)% and 9.42 X 10(-2)% respectively. These results indicate that there exists a potential for the synthesis of cholesterol and dehydroepiandrosterone in vivo. It is suggested that the biosynthetic pathway involved in the synthesis of the latter is; acetyl CoA----cholesterol----pregnenolone----17 alpha-hydroxypregnenolone----dehydroepiandrosterone.