IL17A and breast cancer: In p53-deficient mammary tumour models, macrophage-expressed IL-1β triggers γδ T cells to express IL-17, which induces the G-CSF-dependent expansion and polarisation of neutrophils, which, in turn, suppress the activity of cytotoxic CD8+ T cells.75,77 Consequently, inhibition of TGF-β, IL-17 and G-CSF reverses the phenotype of neutrophils and promotes the activity of cytotoxic CD8+ T-cells to subvert metastasis.75,93,129,131