In order to assess whether PAS may be a potential therapeutic option in prolactinoma patients who are resistant to or intolerant of DA, we evaluated the tumoral SST2, SST5, and D2R expression in these patient groups and examined the in vitro effects of CAB, OCT, and PAS on prolactin secretion by cultured prolactinoma cells. This evidence concerns the gene DRD2 and prolactin-producing pituitary gland adenoma.