Vaping could trigger widespread genetic changes linked to cancer and chronic disease, scientists have warned.A study has found regular e-cigarette users show altered activity in more than 3,000 genes, including many associated with cancer, heart disease and lung conditions.Researchers say some of these changes may be driven not just by how much someone vapes, but what e-cigarettes they use, with certain flavours and types linked to far greater disruption.The findings add to growing evidence that the devices, often marketed as a way to quit smoking, carry their own health risks.However, experts stress the study was small and does not prove vaping causes disease, instead highlighting early biological changes that could signal potential harm over time.Because vaping is relatively new, its full long-term health impact remains unclear. But scientists say heating e-liquids produces chemicals that may affect gene expression and could impair the body's ability to repair damage.In the latest study, published in Frontiers in Oncology, researchers compared gene activity in 83 people, including vapers, smokers and non-users.They found that those who vaped had 'altered expression' in 3,124 genes - meaning these genes were functioning in a potentially damaging way - compared with people who neither smoked nor vaped. Scientists warn vaping could trigger genetic changes linked to cancer and chronic diseases