He et al. Journal of Experimental & Clinical Cancer Research 2011, 30:109 http://www.jeccr.com/content/30/1/109 Page 4 of 9 Figure 1 Transfection efficiency determined by flow cytometry. The transfection efficiency was 97.2% 6 h after transfecting with CDK8-siRNA of HCT116. The ratio of Lipofectin 2000 to siRNA was 4 μL: 4 μL, and the concentration of CDK8-siRNA is 80 pmol/L. Figure 2 CDK8 and b-catenin mRNA expression of CDK-siRNA transfected HCT116 cells detected by RT-PCR. 48 h later of CDK8-siRNA transfection, RT-PCR was performed to detect CDK8 and b-catenin mRNA expression. A: CDK8-siRNA group; B: scrambled siRNA group; C: non- siRNA group; D, E and F represented corresponding internal reference, and M: marker. Results are given as average value of the gray in three target genes and interal controls from three independent experiments.