Cancer Causation by Infections-Individual Contributions and Synergistic Networks

The search for infectious agents playing a role in human carcinogenesis and their identification remain important issues. This could provide clues for a broader spectrum of cancers preventable by vaccination and accessible to specific therapeutic regimens. Yet, the various ways of interacting among different factors functioning synergistically and their different modes of affecting individual cells should bring to question the validity of the term causation. It also should put a word of caution into all attempts to summarize criteria for causality of infectious agents in cancer development. At least in the opinion of these authors, we would be much better off avoiding these terms, replacing causal factor by risk factor and grading them according to their contribution to an individual's cancer risk. (C) 2014 Elsevier Inc. All rights reserved.