An alternative possibility is that b-AP15 exerts its anti-tumor activity by inhibition of anti-apoptotic proteins such as NF-κB, by stabilization of tumor suppressors such as p53, or by stabilization of Myc and Noxa, as has been suggested for the killing of cancer cells by 20S proteasome inhibitors [18]–[23]. Here, PMAIP1 is linked to neoplasm.