Colony formation of K-562 cells after 24 h (upper panel) or 48 h (lower panel) exposure to ErPC3 (20 μm) and ASO-bcr (10 μm), respectively. Colony formation of K-562 cells after 24 h (upper panel) or 48 h (lower panel) exposure to ErPC3 (20 μm) and ASO-bcr (10 μm), respectively. Bars, SD of the mean of three Petri dishes, respectively. An asterisk denotes a significant difference versus the respective control (Kruskal- Wallis test; P < 0.05). Spiro M. Konstantinov et al. Mol Cancer Ther 2002;1:877-884 ©2002 by American Association for Cancer Research