Osimertinib is currently used as a first-line therapy for EGFR-positive cancer, because it is well indicated for cases that are EGFR-TKI-resistant and T790M-positive, even when the patient has poor PS; however, rebiopsy must be seriously considered in patients whose first EGFR-TKI therapy is not osimertinib. Here, EGFR is linked to cancer.