Multiple myeloma, a cancer of the plasma cell, is an incurable but treatable disease. While a myeloma diagnosis can be overwhelming, it is important to remember that there are several promising new therapies that are helping patients live longer, healthier lives. The estimated frequency of multiple myeloma is 5 to 7 new cases per 100,000 persons per year. Accordingly, in the United States, 19,920 new cases are expected to be diagnosed in 2008. There were more than 56,000 Americans living with multiple myeloma in 2005, the most current date these statistics are available.

This section is designed to serve as a fundamental resource for education about multiple myeloma. It provides a detailed overview of the disease and includes:

• Definition
• Causes and incidence
• Symptoms
• Diagnosis
• Classification and staging
• Prognostic indicators
• Myeloma bone disease
• Glossary

Multiple myeloma (also known as myeloma or plasma cell myeloma) is a progressive hematologic (blood) disease. It is a cancer of the plasma cell, an important part of the immune system that produces immunoglobulins (antibodies) to help fight infection and disease. Multiple myeloma is characterized by excessive numbers of abnormal plasma cells in the bone marrow and overproduction of intact monoclonal immunoglobulin (IgG, IgA, IgD, or IgE) or Bence-Jones protein (free monoclonal κ and λ light chains). Hypercalcemia, anemia, renal damage, increased susceptibility to bacterial infection, and impaired production of normal immunoglobulin are common clinical manifestations of multiple myeloma. It is often also characterized by diffuse osteoporosis, usually in the pelvis, spine, ribs, and skull.

Cells destined to become immune cells, like all blood cells, arise in the bone marrow from stem cells (see figure). Some stem cells develop into the small white blood cells called lymphocytes. The two major classes of lymphocytes are B cells (B lymphocytes) and T cells (T lymphocytes). Plasma cells develop from B cells.