STAT3 and cancer: 2016). The proliferation of neutrophil T cells is restrained by the action of GM-CSF on M-MDSCs via the JAK-STAT pathway. JAK-2/STAT-3 inhibition was shown to reduce the number of MDSCs, and these pathways are critical for MDSCs proliferation in cancer (Bayne et al. 2012; Nishimura et al. 2015; Sendo et al. 2019).