EGFR and non-small cell lung carcinoma: A prospective study showed that the supernatant of cerebrospinal fluid (CSF) in patients with EGFR-mutant NSCLC and leptomeningeal metastasis (LM) is a valuable specimen for EGFR mutation testing, demonstrating that the detection rates of EGFR mutations and T790M in cell-free DNA (cfDNA) of CSF were 68.8%, and 14.6%, respectively.