EGFR and lung cancer: The efficacy of second-generation EGFR-TKIs seems to be better than that of first-generation EGFR-TKIs, but this efficacy is not satisfactory in overcoming acquired drug resistance; in addition, the toxic side effects of second-generation EGFR-TKIs are more worrying than those of first-generation EGFR-TKIs.[8,9] KRAS is a signaling pathway downstream of EGFR, and its mutation is one of the mechanisms of tumor formation such as lung cancer.