Animal models for breast cancer prevention research

Breast cancer is composed of a heterogeneous group of diseases which is characterized by differences in genetic mutations/aberrant oncogene expression, histopathological types, and metastatic potentials. Animal models are valuable tools for defining the molecular pathways in breast carcinogenesis. Various promising chemopreventive agents have been generated to target these pathways, resulting in significant progress in breast cancer prevention research. In this article, we review the animal models of breast cancer, including oncogene (c-Myc, Ras, simian virus 40 (SV40) Tag, erbB2/HER2/neu, Wnt-1, IRS-1 and -2, AIB1/SRC-3, etc.) transgenic mice and tumor suppressor genes (BRCA1, BRCA2, p53, etc.) knockout mice. We discuss the current status of the breast cancer prevention studies, with particular emphasis on chemoprevention using selective estrogen receptor modulators (SERMs), progesterone antagonists, aromatase inhibitors, retinoids/rexinoids, peroxisome proliferator-activated receptor (PPAR) γ ligands, vitamin D receptor ligands, cyclooxygenase-2 (COX-2) inhibitors, tyrosine kinase inhibitors, and anti-erbB2 antibodies. We anticipate that the animal models for breast cancer research provide new tools for understanding the molecular mechanisms of mammary tumorigenesis. By utilizing these animal models more effective chemopreventive drugs and intervention strategies are developed for the prevention of human breast cancer in the future.