MDCK-MDR1 and MDCK-BCRP cells supported preclinical and clinical evidence that osimertinib, a potent epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI), may be a promising therapeutic option in the management of brain metastases from non-small cell lung cancer. The gene discussed is ABCG2; the disease is non-small cell lung carcinoma.