Stem Cell Sources

The first bone marrow transplants occurred nearly 50 years ago. Since that time, the main source of stem cells has traditionally been the bone marrow. But during the past decade, doctors have used stem cells from the circulating blood (also called peripheral blood) or umbilical cord.

Hematopoietic (blood) stem cells are immature cells found in the cavities of the body’s bones, which is the bone marrow. Bone marrow produces red blood cells (which carry oxygen), platelets (which help the blood clot) and white blood cells (which are the main agents of the immune system).

Hematopoietic stem cell transplants are used to treat patients whose marrow stops producing the correct amounts or types of various blood cells. These transplants are also used for those who have solid tumors and whose marrow is destroyed by high doses of chemotherapy. Treatment with chemo, growth factors, or both can cause stem cells that were in the bone marrow to circulate in the bloodstream.