Pituitary tumors are clinically categorized by their hormone-secreting characteristics, with over-secretion of growth hormone (GH), prolactin, adrenocorticotropic hormone (ACTH), thyroid stimulating hormone (TSH), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) or clinically nonfunctioning tumors. This evidence concerns the gene PRL and pituitary tumor.