A similar observation has been made with the full-length proteins, and was explained by the fact that Noxa and Bad neutralise only a subset of anti-apoptotic Bcl-2 proteins.12 To test pepNoxa's apoptotic potential, a U266 myeloma cell line was used, whose survival is dependent on Mcl-1.30 However, expression of pepNoxa in this cell line was not sufficient to drive apoptosis, as viability was unaffected and PARP was not cleaved (Figure 6a). This evidence concerns the gene PMAIP1 and plasma cell myeloma.