A medical procedure to replenish the soft tissue within bones that produces new blood cells. Bone marrow transplants are necessary when marrow has been destroyed by drug or radiation therapy for cancer, often leukemia. A bone marrow donor is usually a close relative of the patient.

Dr. Donald Orlic, of the National Human Genome Research Institute's Genetics and Molecular Biology Branch, defines bone marrow transplantation.

Related terms: cancer, hematopoietic stem cell, leukemia, mutation.