Down-regulation of HDGF inhibited cell transformation. The anchorage-independent growth of parental HepG2 cells and their stable derivatives, shCtrl and shHDGF, were examined by soft agar colony formation assay. A. Colonies were photographed. B. Bar graph showed the differences of colony formation among the three groups. Data were presented as mean ± SD for three independent experiments. *P < 0.05, as compared to parental HepG2 cells and shCtrl cells.