Despite potential benefits, studies6,7 have reported that 30% of patients with stage IV EGFR variant–positive NSCLC nevertheless developed rapid tumor progression after EGFR-TKI therapy, and TKIs were deemed ineffective or less effective in these patients.4,8 Currently, there are no known biomarkers predictive of which patients might not benefit from TKIs and are thus at risk for rapid disease progression. This evidence concerns the gene EGFR and neoplasm.