Genistein inhibits breast cancer cells. (A) MCF-7 cells growing in the log phase were treated with increasing concentrations of genistein for 48 hours. The anti-proliferation effect of genistein was measured by Cell Counting Kit-8 (CCK-8;) assay. (B), (C) Genistein reduced the number of colonies in MCF-7 cells. Genistein’s effect on the surviving fraction on MCF-7 cells was detected by colony formation assay. The number of colonies was counted after 7 days. All data presented as mean ± standard deviation (n ≥3). (D) Genistein increased the percentage of late period apoptotic cells labeled with Annexin V– fluorescein isothiocyanate (FITC)/propidium iodide (PI) in MCF-7 cells. Experiments were repeated three times, and similar results were obtained. Representative scatter grams from flow cytometry profile represent Annexin V–FITC (AV) staining on the x axis and PI on the y axis. *P <0.05, Student’s t test. Each condition was repeated three times and error bars represent standard deviations.