Mouse models for multistep tumorigenesis

The mouse is an ideal model system for studying the molecular mechanisms un derlying the pathogenesis of human cancer. The generation of transgenic and gene-knockout mice has been instrumental in determining the role of major determinants in this process, such as oncogenes and tumor-suppressor genes. In the past few years, modeling cancer in the mouse has increased in its c omplexity, allowing in vivo dissection of the fundamental concepts underlyi ng cooperative oncogenesis in various tumor types. In this review, we discu ss how this transition has been facilitated, providing relevant examples. W e also review how, in the post-genome era, novel methodologies will further accelerate the study of multi-step tumorigenesis in the mouse.