CCND1 and breast cancer: To investigate how miR-520e regulates cyclinD1 in breast cancer cells, we searched for the binding sites between miR-520e and cyclinD1 through online software (http://www.targetscan.org) The binding site of miR-520e exists within the 3’ untranslated region (3’UTR) of cyclinD1 mRNA (Figure 3A).