Multiple myeloma: a therapeutic enigma.

Multiple myeloma is one of the few malignancies with a distinct tumor marker, the myeloma protein. This marker, as well as other disease manifestations, can be used to follow the progress of the tumor. Myeloma was also one of the first cancers to respond to chemotherapy and well known are the reports in the early 1960s of good results with melphalan and with cyclophosphamide. Since that time many other agents have been introduced and combination chemotherapy with several drugs were tried extensively. The enigma: Despite the tumor marker and despite the many available drugs there has been very little progress made in improving the outcome of multiple myeloma in the last two decades.