There is evidence that estrogens can stimulate normal and neoplastic lactotrophs’ growth in vitro and in vivo animal models [4, 5]; however, in humans, evidence is limited to a few studies which have shown a positive effect of the postmenopausal state on the course of disease, with spontaneous and progressive reduction of PRL and adenoma size observed in untreated women, and rare cases of hyperprolactinemia recurrence [6–9]. The gene discussed is PRL; the disease is adenoma.