A Systematic Approach to Preclinical Trials in Metastatic Breast Cancer

The process of developing new agents for therapy against breast cancer is inefficient and relies on animal models to screen for efficacy for preclinical studies. However, there has been limited validation of these models, despite the increasing costs in the rapidly growing era of personalized medicine and targeted therapy. Recently, there have been multiple studies which have critically evaluated animal models for breast cancer drug discovery. We recently reviewed the transgenic, xenograft, and syngeneic murine breast cancer models, the ectopic, orthotopic and intravenous methods of cell implantation, tumor gene expression profiles, as well as the ethics of animal experimentation, and we provide important information for investigators in this challenging field. Because of the complexities of treating breast cancer and the increasing costs of developing new agents, the choice of the appropriate murine model must carefully consider each model available, including the tumor gene expression profile. Such a critical approach to the in vivo portion of drug development will further increase the efficiency of breast cancer drug research and development.