Polyoma virus: Old findings and new challenges

The accidental discovery of the mouse polyoma virus nearly 50 years ago ope ned up an experimental system unique in opportunities for investigating vir us-host interactions leading to the development of tumors. Extensive studie s of the virus in tissue culture have provided a detailed understanding of its genetics and molecular biology. Knowledge of the virus as a transformin g agent in culture can now be tested in the animal where multiple cell type s are targets for tumorigenic conversion and where a variety of host factor s, both immunological and nonimmunological, come into play. Studies in the animal using well-characterized wild-type and mutant virus strains have led to some unexpected findings. Some of these run counter to certain widely h eld beliefs in cancer biology. This minireview focuses on these surprising findings and the challenges they raise. (C) 2001 Academic Press.