EGF and polycystic ovary syndrome: In addition to steroids, other factors, which are highly present in the FF of PCOS (when compared to normal matched for FF-volume), can also down-regulate aromatase activity, such as anti-Müllerian hormone (AMH) [103], epidermal growth factor EGF [104], or/and interleukin-6 (IL-6) [83,105].