Granulocyte-macrophage colony-stimulating factor and granulovyte CSF are given to stimulate white blood cell formation in cancer patients who are receiving chemotherapy, which tends to kill their red bone marrow cells as well as the cancer cells. Thrombopoietin shows great promise for preventing platelet depletion during chemotherapy. CSFs and thrombopoietin also improve the outcome of patients who receive bone marrow transplants.