Cancer is a family of diseases, all involving a series of genetic changes that enable cells to grow in an uncontrolled manner, and show other features of cancer, in the human body . Viruses, by nature of their need to hijack normal cell processes to replicate, inject their genes into human cells; this injection can then cause the sorts of genetic changes required to trigger these features.
Modern research now very strongly links subtypes of HPV with cervical cancer , even more so than in the dated references Judy provides. While it is highly likely there are other factors associated with the development of cervical cancer , especially given that cancer involves a set of stages of development , I note the following:
*) Since HPV appears to be the necessary condition , immunisation of even some of the strains involved presents a clear line of attack to reduce the risk of developing cervical cancer.
*) It is unlikely that sexual behaviours as such are co-factors, as Judy suggests, rather these are just correlations by virtue of the fact that sexual practices carry different chances of transmitting HPV, the underlying causal factor.
*) Although there may be a low risk of HPV progressing to cancer, and not all of those who get cervical cancer will die, when one compares this with the risks from vaccines, the balance is clearly in favour of using vaccines to prevent what is, for those who do get cervical cancer, a nasty disease.
1. Hanahan & Weinberg, Hallmarks of cancer: the next generation, Cell 2011.
2. Walboomers et al., Human papillomavirus is a necessary cause of invasive cervical cancer worldwide, The Journal of Pathology 1999.
3. Hildesheim et al., HPV co-factors related to the development of cervical cancer: results from a population-based study in Costa Rica, British Journal of Cancer 2001.