PIK3CA and central nervous system cancer: The oncogene metadherin (MTDH), first identified bioinformatically as a direct target gene of miR-202 in glioma, was found to be upregulated and negatively correlated with miR-202 expression in clinical glioma tissues, and targeting of MTDH by miR-202 was reported to inhibit glioma cell proliferation, migration, and invasion via impairment of the PI3K/AKT and WNT/β-catenin pathways [80].