Interestingly, whilst cell cycle effector genes, such as cyclins and cyclin‐dependent kinases, were down‐regulated upon knockdown of DDX3X, expression of the negative regulator of the cell cycle, KLF435, was dramatically increased in MCF7 cells (Fig. 2E) as well as in more aggressive MDA‐MB‐231 breast cancer cells (Fig. S3). This evidence concerns the gene DDX3X and breast cancer.