MAPK1 and neoplasm: For example, heparin‐binding EGF‐like growth factor (HB‐EGF) secreted by the TAMs enhanced tumor cell motility and invasion by activating EGFR, correlating with poor prognosis.[367] EGFR activation in macrophages also promotes pro‐inflammatory cytokine production via MAPK1/3 and NF‐κB signaling, while EGFR‐deficient macrophages exhibit impaired Th1 and Th17 adaptive immune responses to bacterial infection.[361] In addition, in Kupffer cells (resident liver macrophages), IL6 production is strictly EGFR‐dependent.