Purpose: Our objective was to determine the effect of the flavonoid biochanin A (BCA), administered alone or in combination with the flavonoids quercetin and epigallocatechin-3-gallate (EGCG), on the growth of human breast cancer MCF-7 cells in a murine xenograft animal model.
Materials and methods: MCF-7 tumors were implanted into mice and groups of mice were treated with vehicle, BCA at 2 doses (5 or 15 mg/kg), quercetin and EGCG (5 mg/kg each), or BCA combined with quercetin and EGCG (5 mg/kg each). The flavonoids were injected once daily intraperitoneally, with treatment starting 4 weeks prior to cell inoculation.
Results: Treatment with 15 mg/kg of BCA or the mixture of the 3 flavonoids resulted in a reduction in tumor incidence. Tumor size in xenograft mice treated with 15 mg/kg BCA was significantly smaller than in the control group. Although quercetin/EGCG administration did not affect tumor size, treatment with the mixture of the 3 flavonoids at doses of 5 mg/kg produced similar effects as seen with 15 mg/kg BCA.
Conclusions: Our findings indicate that BCA inhibits tumor growth in a xenograft animal model; BCA may represent a breast cancer preventive agent, either administered alone or in combination with other flavonoids.