PAK1 and posterior cortical atrophy: Downregulation of PAK1 was shown to inhibit PCa cell migration and microinvasion via modulation of matrix metalloproteinase 9 and various growth factors.37 Downregulation of HN1 was reported using an AKT inhibitor38 and an increase in HN1 levels increases migration in a PCa cell line model.39 Taken these facts together, decreases in HN1 and PAK1 protein abundance levels offer an early indication of drug effectiveness and inhibits PCa migration.