Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) are effective therapies for advanced lung cancer patients bearing EGFR-activating mutations, but are not curative due to the invariable apparition of resistances. The investigator team have identified a new phenotype related to drug tolerance after EGFR-TKI treatment that shares several characteristics of a known process of Therapy-Induced Senescence (TIS), which could be a major event of drug tolerance in patients. Using cutting-edge technologies, patient-derived xenografts (PDX) and circulating tumor cells (CTC), the investigator team will perform an exhaustive characterization of the phenotypic and molecular changes associated with this drug-tolerant state in patients. Their results should lead to new therapeutic approaches to eliminate the reservoir of drug-tolerant cells and to prevent emergence of resistance mutations responsible for the relapse of patients.