GNAS, which codes for the Gαs protein, is one of the most frequently altered G proteins in various cancer such as appendix cancers (70%), pituitary tumors (27%), endometrial carcinomas (7.3%), stomach adenocarcinomas (5.7%), adrenocortical carcinomas (5.5%), pancreatic adenocarcinoma (5.6%), esophageal carcinomas (4.9%) and colorectal cancers (4.7%) [118]. This evidence concerns the gene GNAS and pituitary tumor.