PIK3R3 and glioma: To explore the effects of circ_0021350 on glioma cell growth in vivo, the U251 cells were separated into four groups: blank control, Lv-circ_0021350-shRNAs transfected group, Lv-circ_0021350-shRNAs + miR-1207-3p antagomiR-co-transfected, and Lv-circ_0021350-shRNAs + pLVX-PIK3R3 co-transfected.