In situ hybridization and IHC, showing similar expression pattern for miR-21, SOX2, and the tumor cell marker OLIG2. Inhibition of miR-21 causes a decrease in SOX2 expression. A) Serial paraffin coronal sections of a Gtv-a p16Ink4a−/−/p19Arf−/− mouse brain showing overlapping expression of miR-21, SOX2, and OLIG2. Scale bar is indicated in the figure and represents 50 μm. Western blot analysis, demonstrating a decreased expression of the stem cell transcription factor SOX2, after LNA-miR-21 in p19Arf−/− mouse primary glioma cultures is shown in B). GAPDH was used as a loading control.