CCND1 and breast cancer: We also checked the roles of cyclin D1 in the self-renewal ability of breast cancer cells by using RFP-based [Correction added on 21 May 2015 after first online publication: TET-on was removed.] shRNA-cyclin D1 in MCF-7 cells (Fig.1E); results showed that knockdown of cyclin D1 inhibited both the stem cell numbers (Fig.1F) and mammosphere size (Fig.1G); representative images are shown in Figure1H.