G-CSF is the master regulator of granulopoiesis, and several studies have shown that inhibition of G-CSF decreases neutrophil-mediated metastasis.75,107,108 GM-CSF is somewhat redundant to G-CSF in neutrophil regulation; although, its expression is dominant in certain contexts.109 Thus, data from mouse models indicate that inhibiting G-CSF and GM-CSF in metastatic cancer patients with neutrophilia to lower neutrophil numbers may reduce secondary tumour formation and/or burden. This evidence concerns the gene CSF3 and neoplasm.