OLIG2 and central nervous system cancer: The PDGFRA-cocluster transcriptomal class shares features with the Proneural group of gliomas identified by Phillips et al using transcription analysis, and is characterized by genes expressed during normal cortical oligodendrocyte development such as olig2, Sox2 and doublecortin and signaling pathways involved in that process as well, such as PDGF and SHH.