EGFR and lung cancer: In addition, the expression levels of lncRNA GAS5 are significantly downregulated in epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI)-resistant lung cancer cells compared with in EGFR-TKI sensitive cells, and in vivo and in vitro experiments demonstrated that GAS5 affects EGFR-TKI resistance by regulating the insulin like growth factor 1 receptor protein (16).