In vivo and in vitro studies proved IGF-1 increase antiapoptotic proteins (such as Bcl-2, Bcl-XL, cIAP-1, cIAP-2, FLIP) and decrease pro apoptotic proteins (such as caspase 3, caspase 8, caspase 9) and plays a role in drug resistance (dexamethasone, rapamycine)[39], [40], [41] Many studies in multiple myeloma have shown that the role of IGF-1 is correlated with signalling pathway activation. This evidence concerns the gene CASP8 and plasma cell myeloma.