Liquid Biopsy as a Diagnostic and Monitoring Tool in Glioblastoma

Abstract

Glioblastoma (GBM) is the most prevalent and aggressive primary central nervous system (CNS) tumor in adults. GBMs exhibit genetic and epigenetic heterogeneity, posing difficulties in surveillance and being associated with high rates of recurrence and mortality. Nevertheless, due to the high infiltrating ability of glioblastoma cells, and regardless of the considerable progress made in radiotherapeutic, chemotherapeutic, and surgical protocols, the treatment of GBM is still inefficient. Conventional diagnostic approaches, such as neuroimaging techniques and tissue biopsies, which are invasive maneuvers, present certain challenges and limitations in providing real-time information, and are incapable of differentiating pseudo-progression related to treatment from real tumor progression. Liquid biopsy, the analysis of biomarkers such as nucleic acids (DNA/RNA), circulating tumor cells (CTCs), extracellular vesicles (EVs), or tumor-educated platelets (TEPs) that are present in body fluids, provides a minimally invasive and dynamic method of diagnosis and continuous monitoring for GBM. It represents a new preferred approach that enables a superior manner to obtain data on possible tumor risk, prognosis, and recurrence assessment. This article is a literature review that aims to provide updated information about GBM biomarkers in body fluids and to analyze their clinical efficiency.

Keywords: CTC; TEPs; biomarkers; cfDNA; cfRNA; extracellular vesicles; glioblastoma; liquid biopsy.

Figure 1

Examples of circulating biomarkers released into the bloodstream by the tumor mass. They can be collected and analyzed for tumor-specific changes.

Figure 2

Profiling cancer-associated genetic alterations in cell-free DNA obtained from body fluids, such as blood or plasma, CSF, urine, and saliva, offers the possibility of screening healthy or at-risk asymptomatic patients for early detection, diagnosis, and treatment of cancer.