Cerivastatin is used in the treatment of hypercholesterolemia to inhibit 3-hydroxy 3-methylglutaryl coenzyme A reductase and thus prevent the synthesis of cholesterol precursors, such as farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP), responsible, respectively, for translocation of Ras and Rho to the cell membrane, a step required for their cell signaling, leading to cell proliferation and migration. Recently, it has been suggested that non lipid-related effects of statins could play a beneficial role in cancer therapy. In this study, we have investigated the mechanisms by which statins inhibit cancer and the types of cancers which could benefit from this therapy. In MDA-MB-231 cells, an aggressive breast cancer cell line with spontaneous activation of Ras and NFkappaB and overexpression of RhoA, cerivastatin induced inhibition of both cell proliferation and invasion through Matrigel. This anti-proliferative effect was related to G(1)/S arrest due to an increase in p21(Waf1/Cip1). The anti-invasive effect was observed from 18 h and could be explained by RhoA delocalization from the cell membrane, resulting in disorganization of the actin fibers and disappearance of focal adhesion sites. The importance of RhoA inactivation in both these inhibitory effects was proved by their reversion by GGPP but not by FPP. Moreover, cerivastatin was also shown to induce inactivation of NFkappaB, in a RhoA inhibition-dependent manner, resulting in a decrease in urokinase and metalloproteinase-9 expression, two proteases involved in cell migration. The participation of Ras inactivation is considered a subsidiary mechanism for the effects of cerivastatin, as they were not rescued by FPP. Prolonged treatment of MDA-MB-231 cells with high doses of cerivastatin induced a loss of cell attachment. Interestingly, the effect of cerivastatin was considerably lower on poorly invasive MCF-7 cells. In conclusion, our results suggest that cerivastatin inhibits cell signaling pathways involved in the invasiveness and metastatic properties of highly invasive cancers.