PAK1 and breast cancer: To test if the down-regulation of the aforementioned genes correlated with PAK1 expression levels, the total amount of PAK1 and its phosphorylation levels were confirmed by western blot in the PAK1 non-amplified breast cancer cell line HCC1419, the PAK1 overexpressing cell lines BT-474 and MDA-MB-361 and the PAK1 amplified breast cancer cell line SK-BR-3 (Figure S1A).