Currently, the diagnosis, prognosis, and treatment selection of lung cancer are mainly accomplished by histologic inspection of tumor tissue [2], lymph node involvement [3], radiological imaging [4], and mutational status of EGFR, KRAS, ALK, BRAF, ROS1, HER2, RET, MET, and PD-L1 expression analysis [5]. The gene discussed is EGFR; the disease is lung cancer.