A later study directed to deepen this latter effect showed that low DUSP4 expression is associated with high MEK1/2 phosphorylation in BC specimens and cell lines (MDA-MB-231, ZR751, MDA-MB-468, SUM159PT, BT549, MFM223, and HCC1143) endowed with cancer stem cell characteristics and that DUSP4 KD enhances mammosphere formation [100]. Here, MAP2K1 is linked to cancer.