HOTAIR and glioma: For example, lncRNA HOTAIR was upregulated in glioma patients and promoted glioma progression through several mechanisms such as acting as ceRNA for miRNA-126-5p and miRNA-326 [13,14], enhancing angiogenesis [15], regulating an 18-gene cell cycle-related mRNA network [16], and activating PI3K/AKT and MEK1/2 pathways [14].