What Is Multiple Myeloma?  - Multiple Myeloma Research Foundation

What is Multiple Myeloma?

Multiple myeloma is a hematological (blood) cancer that develops in the plasma cells found in the soft, spongy tissue at the center of your bones, called bone marrow. Plasma cells are a type of white blood cell responsible for producing antibodies (immunoglobulins) which are critical for maintaining the body’s immune system. Through a complex, multi-step process, healthy plasma cells transform into malignant myeloma cells.

Myeloma cells result in the production of abnormal antibodies, or M proteins. A high level of M protein in the blood is the hallmark characteristic of multiple myeloma. Additionally, all myeloma cells are identical to each other and produce large quantities of the same specific M protein (for example, IgG or IgA). The M proteins offer no benefit to the body, and as the amount of M protein increases, it crowds out normally functioning immunoglobulins. This ultimately causes multiple myeloma symptoms such as bone damage or kidney problems.

Healthy bone marrow and myeloma bone marrow comparison

In healthy bone marrow, B-cells, a type of white blood cell, develop into antibody-producing plasma cells when foreign substances (antigens) enter the body. In multiple myeloma, DNA damage to a B-cell transforms the normal plasma cell into a multiple myeloma cell. The cancerous cell multiplies, leaving less space for normal blood cells in the bone marrow, and produces large quantities of M protein.

Multiple Myeloma typically occurs in bone marrow with the most activity, which is the marrow in the spine, pelvic bones, ribs, and area of the shoulders and hips. In addition, groups of myeloma cells cause other cells in the bone marrow to remove the solid part of the bone and cause osteolytic lesions, or soft spots in the bone, resulting in weakened bones and increasing the risk of fractures. Although common, these lesions or other signs of bone loss do not occur in all patients with myeloma.


Learn more about Multiple Myeloma

Symptoms of Multiple Myeloma
Causes of Multiple Myeloma
Diagnosis of Multiple Myeloma
Complications of Multiple Myeloma
Prognosis of Multiple Myeloma
Multiple Myeloma Treatment Options

Source: DeVita VT Jr, Hellman S, Rosenberg SA, eds. Cancer: Principles and Practice of Oncology. 5th ed. 1997:2350. Adapted with permission from Lippincott Williams & Wilkins.