HOTAIR and glioblastoma: Contrarily, modulation of DNA methylation levels in GBM cell lines by the demethylating agent 5-Aza indicated that intragenic CpGs in HOTAIR locus affected its transcriptional levels in a cell line-dependent manner (globally, most cell lines increased HOTAIR levels upon demethylation, while U87MG did not, possibly attributable to different kinetics of 5-Aza response and/or lack of expression of all necessary HOTAIR transcriptional regulators).