What is HPV?
HPV (human papilloma virus) is a collection of over 100 viruses that can infect humans. HPV is most often spread through skin-to-skin contact, usually sexually. Only a few of these viruses are considered the “cancer-causing” strains, most notably, HPV 16 and HPV 18, the viruses that are currently targeted in vaccines directed against HPV. Infection with a “cancer-causing” strain of HPV does not mean a person will develop cancer. In fact, most infections with HPV do not result in the development of cancer.
HPV and Cancer
HPV is now well-established as playing a role in most cases of cervical cancer, as well as many cases of vulvar, penile, and anal cancers. It is also being implicated in some cases of oral cancer, especially those occurring in young, non-smoking women.
Does HPV Infection Cause Lung Cancer?
The possibility that HPV may play a role in the development of lung cancer was first suggested in 1979. Several studies since that time have found evidence of HPV DNA in lung cancers, but this varies significantly depending on geography. In the United States, HPV DNA is found in about 20% to 25% of lung cancers. The most common strains found are HPV 16 and HPV 18, strains that are commonly found with cervical cancer as well.
Whether the presence of HPV in lung cancer indicates causation (that HPV causes lung cancer) is another question. Current thought is that HPV may be a cofactor in the development of lung cancer, that is, the virus may work together with other risk factors such as tobacco or radon to produce a cancer.
The presence of HPV in lung cancer cells is more common in females, non-smokers, and those with adenocarcinoma, a type of non-small cell lung cancer. Interestingly, those people who have evidence of HPV in lung cancer cells appear to have a better prognosis.
So what does this mean for prevention? Minimizing exposure to HPV through safe sex is a good start. Our About.com Guide to Cancer offers more tips on How To Prevent HPV.