IGF1R and plasma cell myeloma: It is of interest to note that although SSTNIGF1R inhibits both IGF-1R and its downstream activation of the αvβ3 or αvβ5 integrin in endothelial and carcinoma cells, the integrin is not active in the myeloma cells, suggesting that it is IGF-1R alone that is required for the survival signaling (40).