E2F1 and central nervous system cancer: We confirmed as previously described [18] that overexpression of miR-138 promotes cell cycle progression and drives glioma cell proliferation (Figure 2B–2D), but this is at odds with the report that miR-138 overexpression in glioma reduced cell proliferation in vitro and tumorigenicity in vivo through inducing a G1/S cell cycle arrest by inhibition of a EZH2-CDK4/6-pRb-E2F1 signaling loop [19].