Viruses in human tumors--personal reflections

A personal view is presented reflecting some developments in human tumor virology during the past three decades. Since the discovery of the Epstein-Barr virus in 1964 members of additional viral groups have been linked to human tumors, e.g. hepatitis B virus, HTLV-1, and a number of different papillomavirus types. It became evident that the virus infection per se is not sufficient and that additional events modifying the host cell genome contribute to the development of virus-linked human cancers. At present approximately 15% of the worldwide cancer incidence can be linked to viral infections. The author describes his personal entry into the field and the research in his laboratory on human tumor viruses.