A panel of leading academic and pharmaceutical investigators takes stock of the remarkable work that has been accomplished to date with proteasome inhibitors in cancer, and examines emerging therapeutic possibilities. The topics range from a discussion of the chemistry and cell biology of the proteasome and the rationale for proteasome inhibitors in cancer to a review of current clinical trials underway. The discussion of rationales for testing proteasome inhibitors in cancer models covers the role of the proteasome in NF-kB activation, the combining of conventional chemotherapy and radiation with proteasome inhibition, notably PS-341, new proteasome methods of inhibiting viral maturation, and the role of protesome inhibition in the treatment of AIDS. The authors also document the development of bortezomib (VelcadeTM) in Phase I clinical trials and in a multicentered Phase II clinical trials in patients with relapsed and refractory myeloma.