It has been shown that IFI6 plays anti-apoptosis roles in gastric and breast cancer cells, human myeloma cells and vascular endothelia cells, mainly through stabilizing mitochondrial membrane potential, inhibiting activation of caspase 3 and caspase 9, and decreasing Bax/Bcl-2 [5, 6, 20]. Here, CASP9 is linked to plasma cell myeloma.