STAT3 and central nervous system cancer: We next investigated in circulating monocytes the activation of STAT3, one of the key players regulating tolerogenic activities of tumor-associated myeloid cells (20), by analyzing p-STAT3 expression in CD14+ cells and found that its intensity significantly increased in all glioma grade compared to HD (Figure 2H), thus suggesting an active involvement of this transcription factor in the modulation of immune suppression.