CSF3 and neoplasm: In DLNs, numbers of MDSCs in 4T1 tumor bearing mice (35 ± 0.5 × 104 MDSCs) was significantly higher than the levels in naïve mice (1.2 ± 0.3 × 104 MDSCs) but not 4T1.G-CSF− tumor bearing mice (Fig. 7a).