Detection of aromatase and estrogen receptors (ERα, ERβ1, ERβ2) in human Leydig cell tumor

A Leydig cell tumor is a rare neoplasm, deriving from the interstitial cells, whose pathogenesis has not been still defined. Leydig cells of normal adult testis are known as physiological targets for estrogens. However, some studies on transgenic rodents suggest a role of estrogens in the development of Leydig cell hyperplasia and Leydig cell tumor. Therefore. with the aim to evaluate a possible link between estrogens and testicular tumorigenesis, this study investigated the expression of aromatase and estrogen receptors (ER alpha, ER beta(1). ER beta(2)) in testes from two patients with Leydig cell tumor. A strong immunoreactivity for aromatase, ER beta(1), and ER beta(2), together with a detectable ER alpha immunostaining, was revealed in tumoral tissues. These findings were confirmed by western blot analysis of tumor extracts detecting a 55 kDa P450arom, a 67 kDa ER alpha band, a 59 kDa ER beta(1) band, and a 53 kDa ER beta(2) band. The pattern of ER expression in neoplastic cells appears different from that of control Leydig cells exhibiting only ER beta(1) and ER beta(2) isoforms. The authors hypothesize how the high estrogen production could play a role in the neoplastic transformation of Leydig cells. while the exclusive presence of ER alpha in tumoral cells could amplify estradiol-17 beta signaling contributing to the tumor cell growth and progression.