Glioblastoma biomarkers: finding a needle in a haystack
Glioblastoma is one of the most aggressive brain cancers. Although this tumor is considered relatively rare, it has considerable clinical economic and social impacts due to the limited success that has been achieved so far for its prevention and treatment. The current drawbacks in early diagnostics are mostly attributable to cancer cells heterogeneity and cerebral localization, which both contribute to reduce the potential diagnostic options, thus making the search for candidate biomarkers more or less like finding a needle in a haystack. However, interesting data emerged from recently published studies attest that the assessment of some epigenetic biomarkers (namely methylguanine-DNA-methyltransferase promoter methylation status, combined measurement of some putative micro RNAs), proteomic analysis and cell-free circulating tumour DNA of circulating cancer cells may pave the way to a paradigm shift in glioblastoma diagnostics. It is hence conceivable that combining these different strategies may yield better diagnostic performance that using one single approach alone. Moreover, the potential identification of specific glioblastoma signatures in cerebrospinal fluid, genetic, epigenetic or even biochemical, will perhaps enable identifying localized cancers much earlier than these biomarkers will appear and be measurable in the bloodstream. Further studies will be needed to explore these promising strategies in the future.