RAC1 and breast carcinoma: Using a RAC1-specific inhibitor (NSC23766, albeit in high concentration, 100 μM) and the dominant negative mutant N17RAC1, they demonstrated that RAC1 inhibition decreased the phosphorylation of ERK1/2 and IκBα, as well as the protein expression levels of BCL-xL and MCL-1 protein in the HER-selected breast cancer cells along with clonogenic growth survival [54].