Cytokines, such as interferons, interleukins, and granulocyte-macrophage colony-stimulating factor (GM-CSF), can boost T cell responses, activate apoptosis programs in cancer cells, delay angiogenesis, stimulate dendritic cell maturation, and slow cancer progression.13,18,24 A disadvantage to the use of cytokines, however, is their short half-life. This evidence concerns the gene CSF2 and cancer.