The aroma and type of vaping device play a key role in genetic modifications.

A Californian study published in the journal Frontiers in Oncology focuses on the effects of vaping on RNA expression by oral epithelial cells[1]. Researchers compared vapers, cigarette smokers, and non-smokers to assess the extent to which exposure dose and certain product characteristics influence transcriptomic changes. The authors note that e-cigarettes are often presented as a "less harmful alternative" to combustible tobacco, but their biological effects remain incompletely characterized. This study aims to better distinguish between the effects of the consumed dose and those influenced by the type of device or the flavor of the e-liquid used.

The research protocol

The team analyzed buccal epithelial cells from 83 adults divided into three groups: 35 vapers, 24 smokers, and 24 non-users. The samples were studied by RNA sequencing, with statistical modeling adjusted for age and sex, to identify genes whose expression differed between the groups.

The researchers also examined several exposure indicators, including the cumulative amount of e-liquid, the cumulative amount of nicotine, the number of years of vaping, pack-years for smokers, and plasma cotinine, a nicotine breakdown product. In vapers, they further studied the effect of device generation and flavor type.

Marked and multifactorial genetic effects in vapers

The study found that both vaping and smoking are associated with dysregulation of gene expression compared to non-users. The study identified 3,124 genes differentially expressed in vapers and 2,180 in smokers, with some overlap between the two groups.

Functional analyses revealed disrupted biological pathways in both cases, including mechanisms related to cancer, the cell cycle, and certain signaling pathways, notably the RHO GTPase Cycle pathway, identified as one of the most affected in both groups. The authors also emphasize that the changes observed in vapers are not exactly the same as those in smokers, suggesting both common and specific molecular effects.

While some modifications (28.8 % overall) are linked to the frequency or quantity of vaped products, a much larger proportion (66.6 %) is associated with the type of flavors and devices used: sweet flavors were associated with 2.9 % modifications in the relevant genes, mint/menthol flavors with 0.9 % modifications, fruity flavors with 31 % modifications, and multi-flavor devices with 64.3 % modifications. Thus, the latest generation of devices, such as mods, were associated with the most significant and consistent modifications in gene regulation.

A complex risk assessment of vaping that calls for more regulation and caution

Researchers find that, compared with tobacco, the biological response to vaping is more heterogeneous and depends more on combined factors, such as the power of the device and the composition of the flavors.

In their conclusion, the researchers argue that vaping assessments cannot be based solely on the quantity consumed. They advocate for a broader and more detailed consideration of flavors and product characteristics within risk assessment frameworks and in public health and regulatory decisions. Mods and other newer devices can deliver higher nicotine levels than previous-generation e-cigarettes, and many also contain potentially toxic additives designed to enhance the vaping experience.

Ahmad Besaratinia, a research professor in population science and public health at USC's Keck School of Medicine and senior author of the study, along with his colleagues, are currently conducting a follow-up study on the chemicals used in vaping liquids to determine which compounds are linked to changes in gene expression:« Once these chemicals are identified, policymakers could require manufacturers to eliminate them or reduce their concentration in e-cigarette products in order to minimize potential risks. »" he said[2].

This study intervenes while the US FDA has just relaxed its regulations on sweet and fruity vaping flavors, under the influence of the tobacco and nicotine industry. Public health experts fear that this decision will worsen initiation and addiction among young people and non-smokers and lead to long-term health risks.

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[1]George J, Tommasi S, Pabustan N, Kessler DM, Thomas ZL, Baezconde-Garbanati L, Siegmund KD and Besaratinia A, Multidimensional exposure architecture shapes vaping-associated transcriptomic dysregulation in oral epithelium, Frontiers in Oncology, published June 1, 2026, accessed June 2, 2026

[2]Zara Abrams, E-cigarette flavor and device type play a key role in vaping-related molecular changes, study finds, Keck School of Medicine of USC, published June 1, 2026, accessed June 2, 2026

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