The activity of genes can be altered with chemical tags that get added to the genome, so-called epigenetic modifications. Researchers have found that people who vape carry epigenetic changes that are similar to what is seen in smokers, compared to non-smokers and non-vapers. Their work also showed that these epigenetic modifications are also found in many different kinds of human cancer and other diseases. The findings have been reported in the journal Epigenetics.
In this study, scientists led by Ahmad Besaratinia, Ph.D., associate professor at the Keck School of Medicine of USC, obtained blood samples from 45 volunteers in three categories: smokers, vapers, and people that did not partake in either. Differences in two epigenetic tags were assessed; the researchers looked at hydroxymethyl groups in the whole genome, and a methyl group in a sequence of DNA known as Long Interspersed Nucleotide Element 1 (LINE-1). Both vapers and smokers were found to have much lower levels of both epigenetic tags compared to people that did not smoke or vape.
"That doesn't mean that these people are going to develop cancer," said Besaratinia. "But what we are seeing is that the same changes in chemical tags detectable in tumors from cancer patients are also found in people who vape or smoke, presumably due to exposure to cancer-causing chemicals present in cigarette smoke and, generally at much lower levels, in electronic cigarettes' vapor."
Previous work by Besaratinia's team has shown that cells taken from the mouths of vapers and smokers have different gene expression patterns compared to healthy controls. Many of the genes with differential expression have been linked to cancer.
"Our new study adds an important piece to that puzzle by demonstrating that epigenetic mechanisms, specifically changes in chemical tags attached to the DNA, may contribute to the abnormal expression of genes in vapers and smokers alike," said Besaratinia.
Vaping is often perceived as a healthier option than smoking, and e-cigarettes are growing more popular among young people. The Centers for Disease Control has estimated that 25 percent of high schoolers use e-cigarettes.
"Considering the established role many genes play in human diseases, this investigation should provide invaluable information, which may have immediate public health and policy implications, said Besaratinia. "The epidemic of teen vaping and the recent outbreak of vaping-related severe lung injury and deaths in the U.S. underscore the importance of generating scientific evidence on which future regulations for electronic cigarette manufacturing, marketing, and distribution can be based."