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Some Lung Cancers Linked to Common Virus, Experts Say
A common virus known to cause cervical and head-and-neck cancers may also trigger some cases of lung cancer, according to new research presented by the Fox Chase Cancer Center at the American Association of Cancer Research (AACR) Annual Meeting 2013, held in Washington, D.C.
Examining tissue samples from lung cancer patients, the researchers found that nearly 6% showed signs that they may have been driven by a strain of human papillomavirus (HPV) known to cause cancer.
Studies from Asia have shown that lung tumors are often infected with HPV. The pattern makes sense, explains author Ranee Mehra, MD — the lungs are located near the head-and-neck region, which is known to be at risk of tumors upon exposure to some strains of HPV.
To investigate, she and her colleagues examined 36 tissue samples from people diagnosed with non–small-cell lung cancer (NSCLC) who had never smoked. The reason they chose nonsmokers, Mehra explains, is that smoking is a major cause of lung cancer — but in nonsmokers, the explanation is often less obvious.
The researchers found that 4 out of 36 samples had signs of infection from two strains of HPV (16 and 18) known to cause cancer. Looking more closely at the two samples infected by HPV 16, Mehra and her team saw signs that the virus had integrated into the tumor’s DNA.
Although this suggests that HPV drives lung cancer in less than 6% of nonsmoking patients, making it a relatively rare occurrence, lung cancer is very common, killing more than 1 million people every year, Mehra noted. Approximately 10% of cases occur in nonsmokers.
“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,” she said.
Researchers need to investigate which factors drive some people to develop cancer after exposure to HPV, so they can better treat those types of tumors, Mehra added.
Source: Fox Chase Cancer Center; April 10, 2013.