David S. Siegel, M.D., Ph.D., chief of the Division of Multiple Myeloma, is one of the nation's foremost authorities on multiple myeloma, a potentially fatal blood disorder that occurs when the blood's plasma cells - which produce antibodies that attack and kill germs - grow out of control and form malignant tumors in various places in the body. Multiple myeloma can also cause anemia, a lowered resistance to infections, excessive bleeding, kidney problems, and pneumonia. Dr. Siegel is one of 11 investigators nationwide who brought the exciting new chemotherapeutic agent Velcade to multiple myeloma patients through his clinical trials with the medication. Velcade is an injectable drug that blocks some of the chemical pathways associated with unregulated cancer cell growth. Dr. Siegel's studies have shown that Velcade slows and halts the progression of multiple myeloma. He has also been involved in clinical trials for Revlimid, a new chemotherapeutic agent, and Xcytes, T cells that are produced to accelerate blood cell recovery after stem cell transplantation. Dr. Siegel's research has almost exclusively focused on multiple myeloma and has been published in many leading medical journals, including the British Journal of Haematology, the New England Journal of Medicine, Blood, and Bone Marrow Transplant.