EGFR and non-small cell lung carcinoma: It suggests that the EGFR double mutation may have a good prognosis.[13] Deletions in exon 19 are the most commonly found EGFR kinase domain mutation in NSCLC, and the predictive effects of this drug-sensitive EGFR mutation is well defined.[14] However, the combination of EGFR 2 mutations may have an effect on its drug response to EGFR TKIs.[15] The incidence rate of double mutation of EGFR has been reported in several studies, however, the clinical significance of EGFR double mutation has not been completely confirmed.[2]