Medically resistant and potentially aggressive prolactinomas are more commonly seen with macroprolactinomas (>1 cm), which, in one retrospective study were found to have a disappointingly low prolactin normalization rate of 36% after surgical resection, as opposed to prolactin normalization in 75% of medically refractory microprolactinomas [5]. The gene discussed is PRL; the disease is Microprolactinoma.