Transfection with miR-34a caused significant decreases in phosphorylated Akt (50% reduction), ERK (65% reduction) and Rb (40% reduction), along with an increase in the tumor suppressive protein p21 (100% increase) in two different glioblastoma cultures relative to control miRNA transfection (Fig. 1). The gene discussed is RB1; the disease is glioblastoma.