For example, several cancer vaccines have used IL-2, IL-1541,42, IL-2143–46, interferon-gamma (IFNγ)47, or granulocyte-macrophage colony-stimulating factor (GM-CSF), and have been tested in clinical trials; the latter candidate, a herpes virus expressing GM-CSF, received FDA approval for treatment of melanoma48. Here, CSF2 is linked to cancer.