HAS2 and central nervous system cancer: HAS2 expression is regulated both at the transcriptional and translational levels; for instance, in response to PDGF-BB and phorbol 12-myristate 13-acetate (PMA) [9,10,11,12], but also through the long non-coding RNA HAS2-AS1 [13] that is elevated in gliomas [14,15].