Western blot analysis of proteins involved in regulation of the cell cycle including the modulation of the E2F1-Rb activity. Breast cancer cell lines MDAMB231 and MDAMB468 were treated with 8 μg/mL lovastatin lactone (Lova Lac) or lovastatin acid (Lova Ac) for 48 hours. Western blot analysis of prohibitin was performed based on MDAMB231 cell extracts, otherwise both cell lines are shown. Densitometry data were normalized based on the amount of β-actin. Data are presented as means ± standard deviations (n = 3) *P < 0.05;**P < 0.05; ***P < 0.001. Gel images were cropped to improve the clarity and conciseness of the presentation. HMGB1, high-mobility group box 1; MCM7, minichromosome maintenance protein 7; MSH2, MutS homolog 2.