Studies have demonstrated the altered Gs and adenylate cyclase activity in human GH-secreting pituitary adenomas [79], Gsα and Giα mutations in clinically nonfunctioning pituitary adenomas [80], and an H-ras mutation in a single aggressive prolactinoma or metastases from pituitary carcinomas [81]. This evidence concerns the gene ADCY1 and pituitary adenocarcinoma.