These known targets included CEBPα, STK40, and E2F2 which had been shown to be downregulated at mRNA level by miR-31-H in ovarian cancer cells [34] and Frizzled3 (Fzd3) and MMP16 which were repressed at the protein level by miR-31 in MDA-MB-231 breast cancer cells [35]. Here, STK40 is linked to breast cancer.