ANNOUNCER: Stem cell transplants are part of a therapy that can sometimes be used to save the lives of people who are seriously ill with certain diseases, especially leukemia and lymphoma.
First radiation, chemotherapy, or both, are used to kill diseased cells in a patient's bone marrow. Then stem cells are transplanted, or transfused, to rebuild the patient's capability to produce new blood cells.
There are different types of stem cells. Those that can turn into blood cells are called hematopoietic stem cells.
NELSON CHAO, MD: Stem cells are mother cells, if you will. They are the seeds that give rise to all our blood elements. So when we look at the blood we have, we have red blood cells, white blood cells and platelets, and they are derived from stem cells, when we talk about hematopoietic stem cells.
ANNOUNCER: Doctors have different ways to harvest stem cells.
NELSON CHAO, MD: There are many sources of stem cells. Most commonly, when we talk about stem cells, in hematology we're really talking about bone marrow stem cells.
ANNOUNCER: Stem cells can also be collected from the bloodstream. Some researchers think a third source of blood should be utilized more often, and that this could save many lives when bone marrow donors cannot be found.
NELSON CHAO, MD: It's the blood that is in the umbilical cord, and basically the way it's collected now is that after the child's delivered, the umbilical cord is clamped and cut, and then the placenta's delivered. And the blood that is in the umbilical cord on the placenta side is collected. So that is blood within the placenta.