First described by Fridlender et al. in mesothelioma in vitro and xenograft model, the tumor-associated neutrophils (TAN) are polarized into a subpopulation of anti-neoplastic (N1) or, through induction by TGF-β within the TME, pro-neoplastic (N2) neutrophils (95). The gene discussed is TGFB1; the disease is neoplasm.