STAT3 siRNA causes a decrease in cell number in glioblastoma cell lines. A. A172 cells were transfected with a STAT3 siRNA (bottom panel) or a control siRNA (top panel). Cells were photographed 72 hours post transfection at 200× magnification. B. A172, U251, T98G, and NHA cells were transfected with STAT3 siRNA or mock transfected with oligofectamine (vehicle). Viable cell numbers were determined by MTS assay 72 hours after transfection. (*) indicates a P value <0.001.