IGF1 and glioblastoma: Further analysis of the ability of this miR-302a-3p/IGF1 regulatory axis to control TMZ resistance revealed that knocking down IGF1 in TMZ-resistant GBM cells (Figures 4(i) and 4(j)) reversed the effects of miR-302a-3p inhibitor treatment on the TMZ IC50 value for these cells (Figure 4(k)).