As already mentioned, studies carried out in cancer patients originally showed that LDNs/PMN-MDSCs correlate in vivo with reduced T-cell receptor ζ chain expression and ex vivo with decreased production of cytokines such as interferon-γ (IFN-γ), interleukin-4 (IL-4), tumor necrosis factor-α (TNF-α), and IL-2 by phorbol-myristate acetate (PMA)- and ionomycin-stimulated T cells.28 Interestingly, neutrophils with similar properties were also described by Vasconcelos et al.40 in the peripheral blood of GDs (Fig. 4). Here, IL4 is linked to cancer.