Tumour-derived TNF-α promoted neutrophil activation and neutrophil B7-H2 expression through the extracellular signal-regulated kinase-nuclear factor kappa light chain enhancer of activated B cells (ERK-NF-κB) and the Th producing-IL-17A pathway which was, in turn, polarised in a B7-H2-dependent manner, resulting in pro-tumourigenic roles [206]. The gene discussed is IL17A; the disease is neoplasm.