Since gastrin appears to be an important growth factor of various tumour cell types (Dockray et al, 2001, 2005; Richards et al, 2004), and since some gastric carcinoids have been shown to express the CCK2 receptor (Smith et al, 1998), we examined whether gastrin could affect growth of carcinoid tumour cells as well. This evidence concerns the gene GAST and digestive system neuroendocrine neoplasm.