CSF3 and cancer: Interestingly, we also found that in vivo G-CSF/CSF3 signaling was primarily between fibrocytes and neutrophils or M2 macrophages suggesting robust activation of these suppressive immune cells in the cancer microenvironment, data which was corroborated by increased expression of suppressive cytokine and chemokine genes (Fig 6) strongly suggesting a role of M2 TAMs in chemotherapy-induced protumor signaling [62].