Multiple myeloma is a disease of plasma cells, a type of bone marrow cell. These cells are very important in making immune-fighting proteins called antibodies (immunoglobulins).
In multiple myeloma, cancerous plasma cells grow uncontrollably. They make too much of one specific immunoglobulin that does not fight infection. The cancerous plasma cells crowd out normal plasma cells and other immunoglobulins needed to adequately fight infections.
The mainstay of treatment is chemotherapy, as your friend is receiving. Sometimes treatment includes radiation. Over the past 5 years, remarkable progress has been made in treating multiple myeloma. Several new drugs have been approved to treat the disease.
Another recent development is the use of stem cells through bone marrow transplantation. The goal of this treatment is to completely eliminate the cancerous plasma cells. Before the chemotherapy, bone marrow stem cells are removed from the patient. They are kept in a laboratory where they grow.
High doses of chemotherapy wipe out the patient's bone marrow -- both the cancerous and healthy cells. The stem cells removed before chemotherapy are put back into the patient's body. If everything goes well, the stem cells start producing only normal bone marrow cells and no cancerous plasma cells.
In general, patients can receive one stem cell transplantation. (On occasion, a repeat transplantation may be considered.) However, there can be significant complications from undergoing this procedure. Side effects from the high doses of chemotherapy take a toll on the patient. The patient may not be able to tolerate another transplantation if the first one was not completely successful in eliminating the myeloma.