I. Brain metastasis is an important factor affecting the prognosis of patients with non-small cell lung cancer. Because conventional chemotherapeutic drugs usually have difficulty in crossing the blood-brain barrier, the treatment effect on brain metastasis is poor. Some studies have shown that gefitinib or erlotinib alone or in combination with brain radiotherapy can effectively control brain metastases from non-small cell lung cancer, but there are fewer reports on the efficacy of erlotinib on brain metastases from advanced non-small cell lung cancer. In our first study (Clinical effects of Icotinib for brain metastasis in Chinese non-small cell lung cancer patients harboring an EGFR mutation), clinical observation of the effect of exatinib on 28 cases of The clinical effect of Icotinib for brain metastasis in Chinese non-small cell lung cancer patients harboring an EGFR mutation was observed. This suggests that erlotinib alone is also an effective treatment for patients with brain metastases from non-small cell lung cancer who carry EGFR mutations. Second, although patients with non-small cell lung cancer must be tested for EGFR mutation status before taking TKI drugs, a proportion of patients are not tested for EGFR mutation status due to reasons such as inability to obtain sufficient specimens. Our second study, “Efficacy and tolerability analysis of Icotinib in EGFR mutation-positive and unknown advanced NSCLC patients from Eastern Coastal China,” retrospectively evaluated the efficacy and safety of ercotinib in people with unknown EGFR status and effective first-month trials and in people with EGFR-sensitive mutations. The clinical study involved a total of 342 patients with stage IIIB/IV non-small cell lung cancer and found no differences in DCR, 1-year survival, or mPFS between the first-month trial effective group (n=168) and the EGFR-sensitive mutation group (n=174). This suggests that experimental treatment with exatinib can be given to patients with unknown EGFR status, and that first-month trial effective patients can have the same good treatment outcome as the EGFR-sensitive mutation population. This study somewhat expands the population of potential benefit from TKI therapy for lung cancer.