EGFR and non-small cell lung carcinoma: The overall incidence of leptomeningeal metastasis in patients with NSCLC has increased in recent years to approximately 3.4% to 3.8%,[1–3] but the incidence is much higher (9.4%) in patients with mutations in the epidermal growth factor receptor (EGFR).[2] The sensitivity of tumors to EGFR tyrosine kinase inhibitors (EGFR-TKIs) is dependent on the specific EGFR gene mutations,[4] and not all patients with EGFR mutations show responses to EGFR-TKIs.[5]