As neutrophils produce PGE2via COX‐2, these results together indicate that neutrophils self‐amplify their recruitment through the TNF‐α‐primed PGE2‐EP2‐NF‐κB‐CXCL1 pathway and recruited neutrophils amplify inflammation for tumour development (Figure 4C). This evidence concerns the gene NFKB1 and neoplasm.