By Amir Khan
A common virus affecting 79 million Americans, already known to cause cervical and head and neck cancers, may also be linked to lung cancer, according to preliminary research findings presented at the American Association for Cancer Research's annual meeting.
The findings, which have not yet been peer-reviewed or published, indicate that two strains of the human papillomavirus (HPV) could be to blame for up to 6 percent of lung cancer cases -- or roughly 12,000 cases a year -- and that the HPV vaccine might prevent at least some of those cases.
Researchers from Fox Chase cancer center looked at tissue samples from 36 non-smokers diagnosed with lung cancer, and found that four of the samples showed signs of infection from HPV strains 16 and 18. In two of the cases, the virus was integrated into the tumor's DNA, giving an even stronger indication that the virus was the cause of the cancer.
"It could simply be a coincidence that they had both lung cancer and HPV," Ranee Mehra, MD, study author and attending physician in medical oncology at Fox Chase, said in a statement. "But the presence of both simultaneously, and the integration of the virus into the tumor's DNA, fuels the hypothesis that they are related."
The findings suggest that lung cancer could be blamed on the HPV virus in 6 percent of cases, a significant number, researchers said. Lung cancer kills more than 1 million people every year, researchers said, although 90 percent of cases are caused by smoking.
"Given how many patients develop lung cancer, if even a small percentage of those tumors stem from HPV, that ends up being a large number of patients," Mehra said in a statement.
Previous studies have also found a link between HPV and lung cancer. Research presented at the 2011 AACS meeting compared 1,633 lung cancer patients to 2,729 controls, and found that those with lung cancer were infected with more strains of HPV than those without lung cancer. However, the research presented at this year's meeting is the first to directly link HPV to lung cancer.
HPV strains 16 and 18 -- the ones found in four of the study subjects -- are the strains that the widely available HPV vaccine aims to prevent, according to the U.S. Centers for Disease Control and Prevention, suggesting that vaccine might prove capable of preventing some lung cancers. The HPV vaccine is currently recommended for boys ages 11-21, and girls ages 11-26, and is known to cause cervical, head and neck, and genital cancers, as well as genital warts.
Researchers cautioned that the study findings will need to be confirmed by future research, since it was based on a small number of cases and has not been peer reviewed.
"These results are very preliminary," Mehra said in a statement, "and not a reason to run to your doctor to find out if you are infected, or panic if you are."
"Common HPV Virus Linked To Lung Cancer, Research Finds" originally appeared on Everyday Health.