Background: Breast cancer is the first cause of mortality by cancer in women in North America and Western Europe. For non-estrogen-dependent tumors as well as for metastatic cancers, current therapies are of limited efficacy. Several animal models have been described but they are imperfect as they are poorly representative of what occurs in real tumors. To overcome some of these limitations, we describe a new orthotopic model of estrogen-independent breast cancer in immunocompetent rats treated with cyclosporin A (CysA).
Materials and methods: Injection of cell suspensions of human breast MDA-MB-231 cancer cells into the mammary fat pad or subcutaneous grafts of solid tumor sections were performed on Sprague Dawley rats receiving intraperitoneally 35 mg/kg of CysA. Tumor growth was measured and monitored by scintigraphy using 18FDG and 99mTc-MIBI.
Results: In both models, tumors grew well but growth rates were different. Cell suspension injections gave rise to tumors with a higher growth rate and the tumors obtained infiltrated the mammary and giving results closer to human pathology.
Conclusion: This animal model with injected cells may provide a new adequate tool for studying breast cancer and developing new therapy strategy.