SSTR1 and cancer: Somatostatin (SST) is a cyclic hormone release-inhibiting peptide with two similar physiologically functional subforms, namely, SST14 and SST28 (extension of SST14 at the N-terminus), that negatively regulates cell proliferation, the release of multiple hormones and cancer suppression via activation of five cognate SST receptors (SSTR1–5)1,2.