CDK4 and breast cancer: On the one hand, we found that knockdown of PRMT1 decreased Cyclin E2, Cyclin B1 and CDK4 expression in MCF7 and MDA-MB-231 breast cancer cells (Fig. 2C, D); on the other hand, we also confirmed that ectopic expression of PRMT1 increased the expression of these mentioned proteins (Fig. 2E).