Toll-like receptor 4 (TLR4), an membrane-bound receptor, may serve as a binding site and signaling transducer of LMF which rapidly induces ROS-mediated endoplasmic reticulum (ER) stress and then activates the PERK-ATF4-CHOP pathway to trigger lung cancer cell death and suppress tumor progression30. This evidence concerns the gene ATF4 and neoplasm.