EGFR and non-small cell lung carcinoma: However, approximately 4%–12% of EGFR‐mutant NSCLC tumors have in‐frame insertions within exon 20, named EGFR Ex20ins, and are generally insensitive to first‐ or second‐generation EGFR‐TKIs due to the modified structures of their kinase domains (except for A763_764insFQEA),6, 7, 8 resulting in a dismal prognosis.9, 10