In retrospect, I have devoted my scientific life mainly to the question to what extent infectious agents contribute to human cancer, trusting that this will contribute to novel modes of cancer prevention, diagnosis and, hopefully, later on, also to cancer therapy.
Most of the infections linked to human cancers are common in human populations; they are ubiquitous. They were present during the whole human evolution process.
Whereas HIV only in recent decades became infectious for humans, high risk papillomavirus types have in all likelihood been with us for millions of years, accompanying the human race since the early days of our evolution.
It is important to note that there exist vast gender differences in the global role of papillomaviruses in human cancers. This is mainly due to the role of this virus family in the induction of cancer of the cervix.
Maybe I should mention it: I was not from the beginning mainly interested in papilloma virus; I was mainly interested in infectious agents in human cancer. So papilloma viruses came up as the most likely candidate from my viewpoint.