Some lung cancers linked to common virus
A common virus known to cause cervical cancer and head and neck may also trigger some cases of lung cancer, according to a new study led by a scientist of Indian origin.
The study of Fox Chase Cancer Center in the U.S. examined tissue samples from lung cancer patients and found that nearly 6 percent showed signs that may have been driven by a strain of the human papilloma virus (HPV), which causes cancer.
If HPV actually plays a role in lung cancer in some patients, the next step is to better understand the tumors that can be treated more effectively. “The ultimate goal is to determine if we can direct our therapies to the specific characteristics of these tumors,” said study author Ranee Mehra, deputy physician medical oncology at Fox Chase.
Studies in Asia have shown that lung tumors are often infected with HPV. The pattern makes sense, said Mehra – the lungs are located near the region of the head and neck, which is known to be at risk of tumors after exposure to certain strains of HPV.
To investigate, she and her colleagues examined 36 tissue samples of people diagnosed with metastatic non-small cell lung who had never smoked, part of the Chase Cancer Center Fox biosample Repository
The reason I chose nonsmokers, Mehra said, is that smoking is the leading cause of lung cancer – but in non-smokers, the explanation is often less obvious.
The researchers found that 4 out of 36 samples had signs of infection from two strains of HPV that cause cancer, 16 and 18. Looking more closely at the two samples infected with HPV 16, Mehra and his team saw signs of the virus had integrated into the DNA of the tumor – which is even more suggestive that infection caused the tumor.
Although this suggests that HPV lung cancer units in less than 6 percent of non-smoking patients, so it is a relatively rare occurrence, lung cancer is very common, said Mehra – killing more than 1 million people every year.
Approximately 10 percent of cases occur in nonsmokers. “Given the number of patients who develop lung cancer, if even a small percentage of HPV stem tumors, which ends up being a large number of patients,” he said.
It is unclear how HPV reaches the lung, he said, patients can simply breathe in. And the fact that these patients have evidence of HPV infection does not necessarily mean that infection of their tumors, Mehra said.
“It could simply be a coincidence that had both lung cancer and HPV. But the presence of both at once, and the integration of the virus into the DNA of tumor fuels hypothesized that are related,” it observed. The study was presented at the annual meeting of the American Association for Cancer Research in the U.S..