Human tumor viruses.

Tumor viruses play an important role for the development of a substantial fraction of human malignancies, including common cancers, such as carcinomas of the cervix uteri, hepatocellular carcinomas, or lymphomas. In the recent past, much progress has been made in elucidating the molecular mechanisms by which human tumor viruses contribute to cellular growth deregulation and carcinogenesis. The picture emerges that different tumor viruses target similar cellular pathways for growth deregulation but, in addition, also have unique properties contributing to oncogenesis. Malignant transformation typically requires additional genetic alterations of the host cell, to which tumor viruses can contribute by destabilizating the cellular genome.