The AGO2 protein is located into the cytoplasm as well as into the nucleus of all the examined epithelial and mesenchymal cell lines, normal (thyroid NTHY ori 3-1, primary mammary HMEC-1 and hepatic stellate LX-2) and cancer (breast cancer MDA-MB-231, melanoma A375 and liver cancer HepG2), exhibiting a punctuate pattern (Fig. 1a and Supplementary Fig. S1a–f). This evidence concerns the gene AGO2 and breast cancer.