MYC and brain cancer: MiR-139 could act as an anti-oncomir to suppress primary malignant brain tumor progression by targeting insulin-like growth factor 1 receptor (IGF-1R), associate of Myc 1 (AMY-1) and peroxisome proliferator-activated receptor γ coactivator 1β (PGC-1β), thus inhibiting the PI3K/AKT and c-Myc signaling pathways 55.