A high concentration of stromal cell-derived factor 1-α (SDF-1α) promotes the expression of Rac1 and mediates the migration and adhesion of breast cancer (BC) cells [115], and an oral contraceptive centchroman could inhibit the migration and invasion of breast cancer cells by blocking the Rac1-PAK1-b-catenin signal axis [116]. The gene discussed is PAK1; the disease is breast cancer.