Hida et al. found mutation in guanine nucleotide-binding protein alpha subunit (GNAS) gene in 4 out of 7 (57%) duodenal adenomas with gastric phenotype, and 2 of the 5 cases (40%) of pyloric gland adenomas, whereas APC, BRAF, KRAS, and CTNNB1 genes were wild-type in all investigated gastric-type adenomas [27]. Here, GNAS is linked to pyloric gland adenoma.