SST and neoplasm: They employed the cyclic hexapeptide somatostatin analogue [125I]MK-678 to evaluate the expression of surface membrane receptors and found that the binding of somatostatin peptides with high SSTR2 affinity and antiproliferative properties were powerful inhibitors of [125I]MK-678 binding to various tumor species, indicating that they can practice antitumor effects via the SSTR2 receptor.