EGFR and neoplasm: Because inflammatory microenvironments release signaling molecules such as the tumor growth factor EGF21, which can serve as a ligand for the EGFR protein, we proposed that the microenvironments may select tumor cells with an EGFR protein that is highly activated by functional mutations in EGFR, which provides a new potential explanation for the frequent and recurrent EGFR mutations in never-smokers.