In a current study, Innsbruck researchers were now able to provide evidence that smoking e-cigarettes is associated with similar cancer-associated changes in cells as smoking cigarettes. Their results appeared in the journal “Cancer Research”.
In collaboration with an international team, Chiara Herzog and Martin Widschwendter, both from the EUTOPS research institute at the University of Innsbruck, analyzed the molecular effects of tobacco and e-cigarettes on the so-called epigenome, i.e. the cell program of different cells. Chemical markings and modifications to the DNA triggered by environmental factors can influence how genes are read – with effects on cell development and even the development of cancer.
Epigenome could change
The epigenome, imagined as “a layer of information” that overlays DNA, can change over the course of life due to a variety of genetic and non-genetic factors, such as aging or lifestyle, it said in a release. For example, smoking or tobacco consumption can affect so-called DNA methylation, which is a central indicator of epigenetic changes.
The team led by Herzog and Widschwendter looked in more than 5,300 samples from around 4,000 people – including blood samples, oral swabs and samples from the cervical area of women – for clues about the effects of smoking cigarettes and e-cigarettes, which do not burn the tobacco , but evaporated, had an effect on different cells: namely on cells that are directly exposed to tobacco (e.g. from the oral cavity) and on cells that are indirectly exposed to tobacco (e.g. cervical cells or cells in the blood).
Variety of toxins
“Smoke contains a large number of toxins. However, the list of ingredients alone does not tell us what biological effects these toxins have on different cells,” explained Widschwendter to the APA: “We were able to measure the biological effect via the epigenome. Our analysis suggests that smoking changes the cellular program in various cells – however, we also observe similar changes through the consumption of e-cigarettes or smokeless oral tobacco such as snus,” explained lead author Herzog.
In addition, the epigenetic changes “remained stable for years in many cells.” From these, the researchers were able to derive the people’s “smoking history”: from samples of the oral mucosa, they were able to determine with an accuracy of over 90 percent whether a person smokes, has smoked in the past or has never smoked. Using the so-called epithelial cells in the mouth, it was also possible to determine with similar precision whether a person was consuming e-cigarettes or oral tobacco. Tobacco products cause a “pro-carcinogenic epigenome” in this type of cells, which are similar to cancer cells of origin in the lungs or other organs – so they show similar changes to cancer cells, it said. And this phenomenon also occurred in the epithelial cells in the mouths of those who consumed e-cigarettes or oral tobacco. “Even if users of e-cigarettes have hardly ever smoked cigarettes before, we observe very similar changes in them,” said Widschwendter, the head of EUTOPS – European Translational Oncology Prevention and Screening Institute.
Effects on body cells examined
The study, which, according to the researchers, was the first to examine the epigenetic effects of smoking and the consumption of e-cigarettes on various body cells, provides “enough evidence that one must at least urge caution when consuming e-cigarettes to quit smoking,” says Widschwendter: “At least at the epigenetic level, e-cigarettes trigger similar changes in cells in the oral mucosa as normal cigarettes, and these changes are similar to those that we observe in various organs during cancer development.”
To know exactly, however, long-term studies are necessary: ”It takes several decades for a tobacco-associated carcinoma to develop. E-cigarettes have only been used with a certain degree of breadth since they were approved in the USA in 2007. Until we have a comparable oncological one “It takes 20 to 30 years to develop a clinical picture that could be observed when smoking cigarettes,” said the doctor and researcher.
