Δ9-Tetrahydrocannabinol (THC) inhibits the epidermal growth factor (EGF)-induced migration and Matrigel invasion of NSCLC cells. A549 cells were treated with different concentrations of THC or with vehicle alone (ethanol) before being subjected to EGF-induced transwell migration (a) and invasion (b) assays. Cells that migrated in response to EGF were normalized as 100%. Data represent the mean±s.e.m. from three independent experiments (**P<0.001; compared to EGF-only stimulated cells).