Multiple myeloma is often referred to simply as myeloma. It is a type of cancer that starts in the plasma cells of the bone marrow. These are protein-making cells which normally make all of the different kinds of proteins that comprise the antibodies of the immune system. In multiple myeloma, the plasma cells undergo what is referred to as a malignant transformation and thereby become cancerous. These myeloma cells stop making different forms of protein in response to the immune system's needs and instead start to produce a single abnormal type of protein referred to as a monoclonal or M protein. Multiple myeloma plasma cell populations accumulate and these collections of cells called plasmacytomas can erode the hard outer shell or cortex of the bone that normally surrounds the marrow. These weakened bones show thinning of the bone such as is seen in nonmalignant osteoporosis or what appear to be punched out or lytic bone lesions. These lesions may cause pain and even breaks or fractures of the bones so damaged.

In traditional Chinese medicine, multiple myeloma belongs to the category of "lumbago", "heumatism" or "consumptive disease".  The disease is cused by the
Six Evils (wind, cold, heat, damp, dryness, fire), diet, emotions, sexual strain, resulting in imbalance of Yin and Yang, disorders of Qi and Blood.

Cause Multiple Myeloma of in western medicine
Several things are capable of causing myeloma or triggering an already abnormal or damaged pre-myeloma cell population in the bone marrow. Several types of things can cause or trigger myeloma: exposure to toxic chemicals, atomic radiation, anything suppressing or interfering with the immune system, or infection with cancer-causing viruses. Toxic chemicals which have been identified include benzene, dioxins (such as dioxins in Agent Orange), and a whole range of agricultural chemicals, solvents, fuels, engine exhausts, and cleaning materials. Serious radiation exposure is rather uncommon, but has occurred in Japan at atomic test and reactor sites, as well as manufacture facilities. Several viruses have been identified, including HIV (AIDS virus), hepatitis viruses, and several herpes viruses. Some retroviruses, such as SV40 (Simian Virus 40), a contaminant in polio vaccine preparations, have also been implicated in the pathogenesis of myeloma.

There is some family tendency for myeloma: approximately 3%–5% of myeloma diagnoses occur in a family member who has a close relative previously diagnosed with MGUS or myeloma. Potential screening/early testing can be discussed with your physician if you have a family member with myeloma or MGUS.