Retraction: Zhang, K., et al. Knockdown of Snail Sensitizes Pancreatic Cancer Cells to Chemotherapeutic Agents and Irradiation. Int. J. Mol. Sci. 2010, 11, 4891–4904, doi:10.3390/ijms11124891 and Zhang, K., et al. RNA Interference Targeting Slug Increases Cholangiocarcinoma Cell Sensitivity to Cisplatin via Upregulating PUMA. Int. J. Mol. Sci. 2011, 12, 385–400, doi:10.3390/ijms12010385 (Int J Mol Sci, 2017)