RPS6KA5 and breast cancer: Msk1 plays a regulatory role in chromatin remodeling in breast cancer cells [38], Ubtf is a known target gene for PRA in human endometrial epithelial cell line [39] and Elk-1 is a member of the ternary complex factor (TCF) subfamily that binds the serum response element found in the promoters of Fos and other immediate early genes [40].