Infectious Agents and Cancer Blog

The real problem is that not only in HPV-associated carcinogenesis, but in the viral oncology in general, and as matter of fact in the whole field of carcinogenesis it is "relatively" simple to identify strong carcinogens; the complexity is to identify weak carcinogenic exposures, implying either the exposure to weak carcinogens that the exposure to minimal/subminimal doses of potent carcinogens. The complexity is not only related to the possible cumulative effect of low carcinogenic exposures and the need for long-term follow up (> 1 year post-exposure), but also to the uncertainty on the background carcinogenic rate (i.e. in vitro transforming activity of empty vectors and even normal human DNA). Stretching any system (not only epidemiology) to the limits could lead to problems on the carcinogenic definition of most (if not all) physical, chemical and biological agents.