From a therapeutic standpoint, the inability of PrP to protect against proteasomal inhibition-induced Caspase 3/7 DEVDase activity implies that up-regulation of PRNP expression would not contribute to chemoresistance in cancers treated with proteasomal inhibitor bortezomib, such as multiple myeloma or mantle cell lymphoma. This evidence concerns the gene CASP3 and plasma cell myeloma.