SST and neoplasm: Somatostatin (SST), as a signal molecule, is mediated by the family of SST receptors (SSTRs) on the cell membrane and plays an important role in inducing cell apoptosis, inhibiting tumor cell proliferation, inhibiting the function of insulin, and inhibiting cell growth and other biological processes [26,27,28], such as SSTR-mediated inhibition of secretion and cell proliferation.