Liquid biopsy and tumor DNA/RNA detection in the cerebrospinal fluid of patients diagnosed with central nervous system glioma - A review article.

Background: Gliomas are the most common primary malignant neoplasms of the central nervous system and their characteristic genetic heterogeneity implies in a prominent complexity in their management. The definition of the genetic/molecular profile of gliomas is currently essential for the classification of the disease, prognosis, choice of treatment, and it is still dependent on surgical biopsies, which in many cases become unfeasible. Liquid biopsy with detection and analysis of biomarkers such as deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) from the tumor and circulating in the bloodstream or cerebrospinal fluid (CSF) has emerged as a minimally invasive alternative to aid in diagnosis, follow-up, and response to treatment of gliomas. Methods: Through a systematic search in the PubMed MEDLINE, Cochrane Library, and Embase databases, we reviewed the evidence on the use of liquid biopsy to detect tumor DNA/RNA in the CSF of patients diagnosed with central nervous system gliomas. Results: After a systematic review applying all inclusion and exclusion criteria, as well as a double review by independent authors, 14 studies specifically addressing the detection of tumor DNA/RNA in the CSF of patients diagnosed with central nervous system glioma were selected in the final analysis. Conclusion: Sensitivity and specificity of liquid biopsy in CSF are still very variable depending on factors such as the diagnostic method, collection timing, biomarker (DNA and RNA), tumor type, extension and volume of the tumor, collection method, and contiguity from neoplasm to CSF. Despite the technical limitations that still exist and prevent the routine and validated use of liquid biopsy in CSF, the growing number of studies around the world is increasingly improving this technic, resulting in promising prospects for its use in diagnosis, evolutionary follow-up, and response to the treatment of complex diseases such as central nervous system gliomas.