[Proteasome inhibitors--new option in the treatment of tumor diseases].

Chemotherapy itself probably will not substantially improve the prognosis of cancer patients in the future. Therefore new methods are needed one of the promising option is the direct interference with intracellular metabolism--"the targeted therapy". Proteasome inhibitors are the example of this new approach and bortezomib is the first agent in this class, which enters clinical trials. We summarize theoretical background and the first clinical experiences with this drug.