Roy S. Herbst, MD, PhD of Yale Cancer Center discusses screening for EGFR mutation and why all lung cancers should be screened. Screening is important because doctors should know whether patients have T790 M and because osimertinib targets these T790 M. Although this has been implemented in the country and the numbers are going up, still its not 100%. Therefore, every lung cancer patient, those who know people with lung cancer and even physicians should screen their patients for EGFR mutation and to check patients whether they have T790 M or not. Regardless of the results, osimertinib has a big role for lung therapy.