Although treatment of patients suffering from leukemia improved throughout the last decades, new chemotherapeutic agents are still required to further minimize side effects and increase overall survival rates. Many leukemia patients still suffer from a relapse following initial therapy (1–4). Since patients with a relapse often prove more resistant to chemotherapeutics, it is important to develop new drugs that act through other cellular pathways to minimize cross-resistance and increase response. In this context, the use of proteasome inhibitors might prove a huge step forward, since these inhibitors not only act on a very powerful regulatory target but also influence several cellular pathways simultaneously. Moreover, these drugs may sensitize malignant cells to conventional anticancer drugs.