The proteasome: A suitable antineoplastic target

The proteasome is an abundant multi-enzyme complex that provides the main pathway for degradation of intracellular proteins in eukaryotic cells. As such, it controls the levels of proteins that are important for cell-cycle progression and apoptosis in normal and malignant cells; for example, cyclins, caspases, BCL2 and nuclear factor of kappaB. A proteasome inhibitor bortezomib - has been developed that has shown efficacy as an anticancer agent in the clinic. How can targeting such a universal, broadly active cellular component provide the selectivity and specificity that are required for cancer therapeutics?