Mehr Ali Mahmood Janlou
Mohammad Kordkatouli
Seyed Abolghassem Mohammadi Bondarkhilli
Mohammad Maroufi

Background: E-cigarettes have become popular as an alternative to traditional smoking but their long-term health effects, especially regarding cancer risk, are concerning. This review evaluates the potential carcinogenic effects of e-cigarettes, focusing on DNA damage, epigenetic changes, and tumor-promoting pathways that may promote tumor development. Materials and Methods: A literature search on PubMed, Scopus, and Web of Science databases yielded studies on e-cigarettes and cancer risk from ۲۰۱۰ to ۲۰۲۴. The employed keywords included "e-cigarettes", "vaping", "cancer risk", and "toxic chemicals". Studies included data on e-cigarette vapor composition and health effects, excluding those on smoking cessation. Data extraction covered study design, population, e-cigarette type, usage, health outcomes, and vapor analysis. Quality was assessed using the Cochrane risk of bias tool and the Newcastle-Ottawa scale. Results: Research indicates that e-cigarettes can cause DNA damage and epigenetic changes that potentially lead to cancer. DNA methylation can alter gene expression and cause mutations, particularly in the respiratory system, increasing cancer risk. Short-term use of e-cigarettes induces lung cancer-related tumor-promoting factors and metastasis in small bronchial tubes. Nicotine inhalation from e-cigarettes can promote tumor growth by stimulating angiogenesis and inhibiting apoptosis, despite nicotine not being a carcinogen. E-cigarette vapor contains known carcinogens like formaldehyde and acetaldehyde, further contributing to cancer risk. Conclusion: Exposure to e-cigarette vapor causes gene expression changes and epigenetic damage similar to those from combustible cigarette smoke, potentially leading to cancer. DNA methylation can change gene expression and cause mutations, especially in respiratory cells.