The pro-tumour function of neutrophils can be implicated in tumour initiation by prostaglandin E2 (PGE2) expression [194], the promotion of tumour growth by TNF-induced IL-17-producing CD4+ T cells [195] and by matrix metalloproteinase 8 or 9 (MMP8-MMP9 that remodel the ECM and induce angiogenesis [196]. The gene discussed is MMP9; the disease is neoplasm.