Multiple myeloma is a cancer of plasma cells involving primarily the bone marrow, which releases a distinctive protein into the blood used for diagnosis. The disease usually occurs in older adults, with approximately 16,000 new cases diagnosed each year in the United States, according to the College of American Pathologists. Protein electrophoresis is an important laboratory test used for diagnosing and monitoring the course of myeloma.
Multiple Myeloma
Plasma cells are a specialized type of lymphocyte responsible for making the immunoglobulins, or antibodies, that circulate in the bloodstream to help fight foreign invaders like bacteria. Multiple myeloma is a cancer arising from these cells, resulting in a large population, or clone, of malignant plasma cells all producing an identical immunoglobulin protein. This growing population of myeloma cells replaces normal bone marrow cells, destroys bone, and releases large amounts of immunoglobulin that causes suppression of normal antibodies and kidney damage. The resulting signs and symptoms include anemia, bone pain and fractures, high blood calcium levels, fatigue, and increased susceptibility to infections.
Protein Electrophoresis
The defining feature of multiple myeloma is the overproduction of large amounts of identical, or monoclonal, immunoglobulin that is found in the blood. Protein electrophoresis is a lab technique that separates all the different proteins in the blood or other body fluids into a few general subgroups, according to Lab Tests Online. Blood serum is placed on a specialized gel paper and an electrical current applied, causing the proteins to migrate across the paper at different speeds based on their electrical charges. In myeloma, an abnormal sharply defined band of protein in the immunoglobin zone is found representing the monoclonal myeloma, or "M," protein. The surrounding normal immunoglobulins are usually decreased in amount.
Diagnosing Multiple Myeloma
When a person presents with symptoms suggestive of multiple myeloma, a variety of tests are ordered, according to the American Cancer Society. A complete blood count tests for anemia or other changes that could be caused by bone marrow replacement. Serum and urine protein electrophoresis is performed to look for abnormal proteins in the blood or urine, and allows for confirmation that an abnormal protein is a myeloma protein. X-rays searching for destructive bone lesions can help determine the stage of the disease. The final diagnostic test is a bone marrow biopsy, which involves inserting a needle through the back of the pelvic bone and removing a small sample of marrow. This material is then examined under a microscope to look for increased numbers of abnormal plasma cells, the malignant cell of myeloma.
Treatment and Follow-Up
The treatment of multiple myeloma is determined by the stage, or extent, of the tumor and related symptoms. Some people are discovered with very low levels of M protein and no symptoms, and might simply be followed by serial immunoglobulin measurements. In more advanced myeloma, a variety of chemotherapy drugs have been found to be effective, along with the steroid prednisone. Radiation therapy can be used to treat destructive bone lesions because of pain or fear of possible fracture. Bone marrow transplant has also been tried when other methods are unsuccessful. Both during and after treatment, regular monitoring of immunoglobulin levels, blood counts and kidney function will be performed.
