Researchers at the Francis Crick Institute (FCI) say while vaping is safer than smoking cigarettes, the long-term health risks are unclear.
Around 3.6 million people in Britain smoke e-cigarettes and are commonly used by ex-smokers to help them quit.
Professor Charles Swanton, clinical scientist at the FCI and chief clinician at Cancer Research UK, says vaping poses a potential threat to people’s health.
“I don’t think we can say vaping is necessarily a safe option to quit smoking. It may be safer but that doesn’t mean it’s safe,” he said.
“We don’t know for certain that vaping won’t cause lung cancer ten years from now.”
Researchers at the FCI conducted studies to understand why some of those diagnosed with lung cancer in the UK – around one in eight patients – are non-smokers, despite smoking being one of the leading causes for the disease.
They used studies on humans and mice which measured exposure to sooty pollution particles in the air that can cause the growth of cancerous cells in the lungs.
Their evidence suggests that the pathway that causes tumours in non-smokers is different to those caused by smoking, which is thought to trigger a direct mutation to DNA that can result in cancer.
Their findings suggests that irritants such as air pollution cause inflammation, which is then followed by a healing process that “wakes up” dormant cells that can cause cancerous mutations and researchers worry that vaping may trigger the same process.
While scientists believe anti inflammatory drugs could help stop the process which can cause cancer, they warn this could be years away.
Professor Swanton said: “The mechanism we’ve identified could help us to find better ways to prevent and treat lung cancer in never smokers. If we can stop cells from growing in response to air pollution, we can reduce the risk of lung cancer.”
Dr William Hill, another researcher at the FCI, said: “Finding ways to block or reduce inflammation caused by air pollution would go a long way to reducing the risk of lung cancer in people who have never smoked.”