Biomarker discovery in central nervous system neoplasms: Past, present and future
Brain tumor biomarkers have long been used as diagnostic tools; they are now finally being brought to bear as therapeutic elements in the fight against brain cancer. Because of the heterogeneity of glial brain tumors, it is clear that no one marker will ever define or defeat them: this has been understood since early days of the search for brain tumor biomarkers. In this chapter, therefore, we provide a context for the trajectory of current research by first discussing the history of brain tumor biomarker research. This is followed by a discussion of the immunologic, cytogenetic, biochemical, and molecular approaches that are currently being used to discover, characterize, and exploit the aberrant features of brain tumor cells. Major biomarkers that have been discovered during decades of research are covered in the earlier sections: gangliosides, tenascin, EGFR and its mutant form EGFRvIII, and GLI. Later sections describe newer, high-thoughput analyses such as gene expression analysis and integrated genome analysis, and outline their role in the discovery of more recent promising biomarkers including doublecortin, osteonectin, semaphoring3B, OTX2, and IDH1 and IDH2. A combination of old and new approaches that harnesses the power of multi-institutional and international cooperation has greatly accelerated the rate of discovery in this field, and is bringing us closer to our goal of finding cures for brain cancers.
