HOXA9 and glioblastoma: In both U251 and U87MG-HOXA9, ChIP-qPCR revealed significantly increased HOXA9 occupancy of the promoter region of HOTAIR in comparison to their respective controls (Figure 2D and 2E; p < 0.0002 for U251; p = 0.0148 for U87MG-HOXA9), confirming that HOXA9 directly interacts with the promoter region of HOTAIR. Together, these results indicate that HOXA9 is a direct activator of HOTAIR expression in GBM cells, thus supporting the strong co-expression of these genes observed in glioma cell lines.