Cerebrospinal fluid as a medium of liquid biopsy in the management of patients with non-small-cell lung cancer having central nervous system metastasis

The molecular profiling of tumors is fundamental in the management of advanced non-small-cell lung cancer (NSCLC). A tissue specimen obtained from biopsy is needed for diagnosis and mutation analysis. However, this may not be feasible for some metastatic sites, such as central nervous system (CNS) lesions, particularly for repeated biopsy. Liquid biopsy with plasma is an emerging tool for molecular testing and could be a surrogate method if tissue cannot be obtained. However, the use of plasma is limited for the detection of mutations arising from intracranial lesions. Cerebrospinal fluid (CSF) was recently demonstrated to be an alternative material for genetic testing in patients with NSCLC having CNS metastasis. In this review, we discuss recent advancement in the use of CSF as a medium of liquid biopsy in patients with NSCLC.