However, a recent study reported that the EGFR exon 20 mutation was heterogeneous in its response to TKIs, some of which were pan-sensitive to EGFR TKIs, while EGFR 20IN-L was only sensitive to second-generation TKI (25), which suggested that the young lung cancer group still needed more caution when treatment selection and when monitoring after receiving EGFR-TKIs treatment. This evidence concerns the gene EGFR and lung cancer.