PGRMC1 and breast cancer: Levels of molecular markers associated with cell-cycle progression, CDK4 and Cyclin D1, also decreased following PGRMC1 silencing (Fig. 3e and Supplementary Fig. 8a, b), whereas the expression of pro-apoptotic markers, Bax and cleaved-caspase 3, increased in both breast cancer cell lines (Fig. 3f and Supplementary Fig. 9a, b).