VPA-mediated increase in histone H3 acetylation and in caspase-2 and caspase-3 activation was confirmed in both AR-positive (LNCaP and C4-2) and in AR-negative (DU145 and PC3) PCa cells, where even lower doses of chronically administered VPA (10–14 days) resulted in a marked decrease in cell proliferation rate and in a significant reduction of tumor xenograft growth in vivo [127]. Here, AR is linked to neoplasm.