PCNA and glioblastoma: qRT-PCR assays showed that exogenously expressed miR-1258 significantly reduced PCNA and MMP2 mRNA expression in GBM cells, and the restoration of E2F1 effectively rescued the inhibitory effect of miR-1258 (miR-1258+E2F1 vs. miR-1258+EV p < 0.05, Figure 5D).