In this study, we show that, similar to the pan-HDAC inhibitor, inhibition of HDAC1 resulted in a significant enhancement in the anti-cancer effects of statins both in vitro and in vivo, and that down-regulation of GGTase-Iβ expression by the inhibition of HDAC1, resulting in inactivation of RhoA, was responsible for this enhancement. The gene discussed is HDAC9; the disease is cancer.