KRAS and lung cancer: Induction of proliferation and anchorage-independent growth was also observed in human lung cancer PC9 cells which carry a Glu746-Ala750 deletion mutation in exon 19 of the EGFR gene, while in human A549 lung cancer cells with KRAS-mutations but wild-type EGFR PM2.5 exposure only induced a transient EGFR activation and a nonsignificant increase in anchorage-independent growth [302].