Liquid biopsy of circulating tumor DNA in cerebrospinal fluid for early diagnosis of brain malignancies: A review

Abstract

Brain cancer is the most aggressive intracranial disease: once diagnosed, 70% of patients will not survive. Early and accurate diagnosis is essential to improving the survival rate of diagnosed patients. Currently, imaging scans and pathological biopsies are mainly relied on to confirm the diagnosis of brain tumors. However, imaging scans do not confirm the diagnosis or tumor grade, nor do assess response and monitor treatment effect. Similarly, pathological biopsies are highly invasive and difficult to repeat. To address these limitations, the field has proposed the use of cerebrospinal fluid (CSF) as a liquid biopsy method to detect circulating tumor DNA (ctDNA). This review focuses on how liquid biopsy of CSF ctDNA can facilitate and complement the clinical care of patients with brain tumors. Relevant reviews in the past five years show that ctDNA is highly expressed and its content in CSF is higher than that in plasma. By sequencing the ctDNA of CSF, the diagnosis and prognosis information of brain tumors can be obtained, the best treatment method can be selected, the treatment response can be monitored, and the tumor evolution can be tracked. Because ctDNA detection is still in the research stage and lacks standardized technology, its effectiveness and practicality require further investigation before they can be used in clinical practice.