MDM2 and cancer: The results of our experiments on the temperature dependence of PNC-27-induced tumor cell killing (Figure 6) suggest that, as with pore-forming proteins such as streptolysin, PNC-27 induces pore formation in two discrete steps: a binding step in which it complexes with HDM-2 in the cancer cell membrane and a subsequent diffusion step in which the PNC-27-HDM-2 complexes fuse together in the cell membrane to form the pores.