Paediatric brain tumours are the leading cause of tumour-related mortality in children. There is a widespread search for predictive biomarkers of brain tumours – any measurable substance that may inform about residual disease, therapy response and/or tumour recurrence.
Generally, blood samples are scanned for known biomarkers, but the blood-brain barrier presents a major hindrance to this process for brain tumours. Instead, cerebrospinal fluid (CSF) is a potential medium for the detection of biomarkers.
A recent study analysed CSF collected from extra ventricular drainage (EVD). The aim was to use CSF – which is usually considered a waste product of EVD – to seek predictive protein biomarkers.
The sample included 29 children bearing brain tumours, and 17 controls who underwent EVD for unrelated causes. The researchers then conducted a proteomic and bioinformatic analysis of the samples.
The researchers identified 1,598 and 1,526 proteins in the CSF of controls and brain tumour patients, respectively. Of these 263 and 191 proteins were exclusive of either condition. Bioinformatic analysis of these proteins revealed two promising proteins that were able to distinguish between control and cancer patients, TAF15 and S100B.
The TAF15 protein plays a role in splicing and mRNA transport, and possesses a potent transcriptional activation domain. This family of proteins are considered to be proto-oncogenic as they form oncogenic fusion genes and proteins. The S100B protein is involved in cell cycle regulation. It is also a clinical marker for brain damage and has potential to allow monitoring of treatment efficacy. Furthermore, there were several biomarkers identified which could distinguish between two large classes of brain tumours.
The biomarkers identified in this study appear highly specific. After further validation, future studies should investigate whether these same biomarkers can be identified through other bodily fluids, less invasively. For example, serum and urine present less invasive options. However, in the search for diagnostic biomarkers, CSF seems to be an appropriate medium for liquid biopsies, adequately reflecting the tumour microenvironment.
Image Credit: Pixabay