Animal models are useful not only for studying and understanding the biological and genetic factors that influence the development of different cancers, but also for developing treatments against those cancers. Unfortunately, although epithelial tissue derived cancers (e.g. breast, colon, lung, skin, and ovarian), are among the most common human cancers, very few models exist for studying the events leading to these tumor types or for testing new therapeutic treatments. Instead, many murine cancer models, incorporating mutations in tumor suppressor genes, typically develop soft tissue sarcomas or lymphomas. Therefore, a mouse model of epithelial carcinomas will facilitate the study and treatment of many common cancers not fully addressed by currently available models.Researchers at the University of California, San Francisco (UCSF), have developed a knockout mouse model of epithelial tissue derived carcinomas. This newly developed cancer model does not rely upon the breeding of multiple generations in order to develop chromosomal instability and is not dependent on homozygous loss of tumor suppressor genes. Instead, following exposure to ionizing radiation, tumor development occurs 2-5 months later and develops in multiple tissues including the ovary, lung, and liver. With their rapidity of tumor onset, wide spectrum of tumors, and decreased animal maintenance, these knockout mice represent a new model for studying ovarian as well as other epithelial derived cancer types and will be useful for the development of therapeutic treatments.