Previous studies have supported the idea that the tumour-associated neutrophils (TAN) promote tumour progression and metastasis by secreting elastase, thereby hydrolysing insulin receptor substrate 1 (IRS1), which blocks the interaction between phosphoinositide 3-kinase (PI3K) and platelet-derived growth factor receptor (PDGFR), thus activating the PDGFR-PI3K pathway 130. The gene discussed is PDGFRB; the disease is neoplasm.