CASC2 and central nervous system cancer: LncRNA CASC2 was reported to be identified as a glioma suppressor gene via miR‐21, while lncRNA XIST is an oncogene that acts as a molecular sponge of miR‐429.39, 40 Among numerous kinds of nonprotein‐coding RNAs, lncRNAs have a key regulatory role in cancer biology.