Granulocyte-macrophage colony stimulating factor (GM-CSF) in the treatment of hematological malignancies

Acute myeloid leukemic (AML) cells not only express receptors for various cytokines but also produce hemopoietic growth factors themselves. Thus, they are able to stimulate their own activation and proliferation, a phenomenon known as autocrine growth. The cell cycle kinetics of AML blast cells are susceptible to stimulation by a variety of cytokines, including granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin (IL)-3, granulocyte colony stimulating factor and stem cell factor. GM-CSF and IL-3 can markedly enhance the cytotoxicity of chemotherapeutic agents by increasing the proportion of AML cells in S-phase at any given time and by altering the metabolic status of the AML cells. A number of clinical studies involving the use of GM-CSF in association with chemotherapy in patients with AML are currently ongoing. In the next few years the first clinical results will become available indicating whether the use of cytokines holds any benefit for patients with AML.