A method of replacing blood-forming cells destroyed by cancer treatment. Immature blood cells (stem cells) in the bloodstream are given to the patient after treatment. This helps the bone marrow recover and continue to make healthy blood cells. A stem cell transplant may be autologous (a patient’s own blood cells saved earlier), allogeneic (blood cells donated by someone else), or syngeneic (blood cells donated by an identical twin). Also called peripheral stem cell support.