© 2000 Khmer Academic Publishers. Printed in the Netherlands Review Strategies to reduce the risk of virus-related cancers

Background: Experimental and epidemiological evidence has established an association between at least eight viruses and various cancer sites. Recent estimates (at least 10 % of cancer worldwide) have revealed that viruses, together with tobacco and diet, account for the largest proportion of cancer in the world. Results: Improvements in the detection of viruses and bio-markers of chronic infection have led to the identification of strong associations with cancer, particularly for human papil-lomavirus (HPV), hepatitis B virus (HBV), and human immu-nodeficiency virus (HIV). For some cancer viruses (e.g., HIV and hepatitis C virus, HCV), the spectrum of malignancies involved has still to be well defined. For HBV and HPV, vaccination aimed at cancer prevention is already a reality or a possibility. Whereas HBV vaccination already emerged as one of the most cost-effective ways to reduce adult cancer mortality, for HPV vaccination some technical problems still await a solution. For other infectious agents (e.g., HCV, HIV) prospects for a vaccine are not immediate. Conclusions: In order to apply new knowledge on viruses to cancer prevention, large vaccination trials are warranted. These will have to be large (many thousands of people), prolonged (5-10 years), and match scientific excellence with a feasible design. Mistrust between scientists and the public will have to be prevented by means of absolute openness in scien-tific information and economical interests involved