A recently identified small subpopulation of reversibly drug-tolerant (DT) cells with >100-fold reduced drug sensitivity has been reported to maintain viability via IGF-1 receptor signaling14 and is supposed to contain residual lesions in mutated EGFR of NSCLC treated with first- and second-generation EGFR-TKIs. This evidence concerns the gene EGFR and non-small cell lung carcinoma.