Multiple myeloma (MM) is a cancer of plasma cells, a subset of the lymphoid lineage that is responsible for antibody production. Transformed plasma cells proliferate uncontrollably in the bone marrow and produce elevated levels of IL-7 and TRANCE/RANK L, which may induce osteolytic bone lesions. Bone damage results in an increased level of calcium in the blood and may contribute to renal failure. Other characteristics of MM include immune deficiency due to increased production of an abnormal immunoglobin protein (M protein) and anemia, which is caused by reduced red blood cell production.
MM is currently incurable and treatment generally begins with high-dose, non-specific chemotherapy. The likelihood of relapse may be predicted based on cytogenetic analysis. For example, malignant plasma cells often contain chromosomal translocations involving an immunoglobin locus with genes such as cyclin family members or fibroblast growth factor receptor (FGF R3). Overexpression of certain cell surface markers, such as CCR1, also has predictive value and may suggest an avenue for novel therapeutic strategies to specifically target pathogenic plasma cells.