PAK1 and breast carcinoma: PAK1 is the best-characterized member of the PAK family, and is involved in various signaling pathways related to innate response, barrier function, epithelial cell migration, and cell survival [53,54], and PAK1 has been found to be upregulated and activated in several types of human cancers including breast cancer, colon cancer, and ovarian cancer [55,56,57].