Multiple myeloma is a quite unique cancer disease that has some specific manifestations and complications. Cancer diseases can arise from all cells in the body. Stomach cancer arises from the mucosa of the stomach; liver cancer arises from liver cells, etc. Multiple myeloma is a “blood cancer” that originates from a subtype of white blood cells known as the B-lymphocytes.
B-lymphocytes are important cells being part of immune response combating the infections and destructing tumor cells. B-lymphocytes are able to produce the-so-called antibodies. Antibodies are proteins with many functions - they bind to bacteria, cancer cells and other intruders of our organism. Antibodies may directly damage their target or make it better visible for the rest of our immune system. The activated B-lymphocytes producing antibodies are also referred to as plasmocytes.
In multiple myeloma, one particular B-lymphocyte turns "crazy", it ceases to respond to body control mechanisms, starts to multiply uncontrollably and its clones spread throughout the body. The ability to produce antibodies is often maintained but the antibodies produced by the tumor cells are usually defective and dysfunctional and we refer them to as the paraprotein.
The exact reason why the disease occurs is not known. The reason is a mutation of the mentioned B-lymphocyte that occurs probably due to a combination of some genetic predisposition and outer factors.
Tumor B-lymphocytes can affect bone marrow of many bones and use it for multiplication. This, however, may disrupt the formation of other cells in the bone marrow. Disrupted production of red blood cells causes anemia manifesting with anemic syndrome (pallor, shortness of breath, dizziness and fatigue), lack of blood platelets followed by increased bleeding and lack of properly functioning white blood cells leading to recurrent infections. The cells of multiple myeloma affect certain bones (typically short and flat bones such as the pelvic bones, spine, ribs and skull bones) causing their decalcification similar to osteoporosis. The condition may result in bone pain and pathologic fractures. The calcium from decalcified bones may get to blood causing hypercalcemia with all its negative consequences.
Paraprotein circulating in the blood leaks into the urine through filtration units of the kidneys (glomeruli). It can accumulate in kidney tissue and impair their functions. In addition, fragments of paraprotein may deposit in other organs and cause their failure - this process is known as AL amyloidosis.
We are interested in occurrence of the above-mentioned symptoms supported with abnormalities in blood test (elevated blood proteins level due to paraprotein presence, anemia, lack of platelets and white blood cells) and positive finding of bone X-ray. The paraprotein may be often confirmed in urine (as the so-called Bence-Jones protein). Sternal puncture helps to obtain a sample of bone marrow cells allowing confirming the presence of tumor B-lymphocytes.
The disease is usually treated by hematologists. Simply said, the primary method of treatment is chemotherapy and in some cases, the disease may be cured by a bone marrow transplant. Symptomatic therapy is focused on analgesic therapy and administering drugs against bone decalcification (for example the bisphosphonates). Excessive amount of paraprotein may be removed from blood by plasmapheresis. When there is present an acute kidney failure, dialysis may be used to replace the disrupted kidney functions.