In patients being treated with high doses of chemotherapy or radiation therapy, the removal of stem cells (the precursors to red and white blood cells and platelets) from the patient’s blood before treatment and their reinfusion after treatment. Granulocyte colony stimulating factor, erythropoietin, and other growth factors are administered to stimulate proliferation of the stem cells after reinfusion. Until adequate numbers of cells repopulate the patient’s marrow and bloodstream, the patient is at high risk for infection and bleeding.