The effect of granulocyte and granulocyte-macrophage colony stimulating factors on tumor promotion

GM-CSF and G-CSF are capable to regulate the maturation of undifferentiated multipotent stem cells into mature granulocytes, macrophages and T cells in the bone marrow. Thereby, clinicians correct neutropenia induced by chemotherapy or radiation routinely with recombinant G- or GM-CSFs in clinical practice. However, relevant studies found that treatment for cancer patients with adjuvant G-/GM-CSF would occasionally enhance the progression of tumors. Besides, constitutive production of G-CSF or GM-CSF by lung cancer cells could stimulate the growth or the invasion of tumor and result in protecting the tumor against unfavorable environment. These findings convinced researchers that G-/GM-CSF overexpression has a positive effect on malignant tumor progression. The purpose of this article was to explore the most recent research and the mechanisms of GM-CSF and G-CSF-induced tumor promotion and their clinical therapeutic applications.