Successful development of cyclic octapeptide SST analogue drugs (octreotide or lanreotide) and their commercial application in hormone release arrest or cancer suppression56,57, together with structural analysis of the SSTR2–Gi complexes bound with SST14, octreotide or lanreotide, provided a great example for further rational optimization of SST analogues with increased selectivity for and higher metabolic stability with other SSTR members. Here, SSTR2 is linked to cancer.