Vaping and lung cancer – A review of current data and recommendations

Abstract

Lung cancer is the most common cause of cancer mortality worldwide and, while tobacco smoke remains the primary cause, there is increasing concern that vaping and E-cigarette use may also increase lung cancer risk. This review concentrates on the current data, scholarship and active foci of research regarding potential cancer risk and oncogenic mechanisms of vaping and lung cancer. Materials and methods: We performed a literature review of current and historical publications on lung cancer oncogenesis, vaping device/e-liquid contents and daughter products, molecular oncogenic mechanisms and the fundamental, potentially oncogenic, effects of electronic cigarette smoke/e-liquid products. Results: E-cigarette devices and vaping fluids demonstrably contain a series of both definite and probable oncogens including nicotine derivatives (e.g. nitrosnornicotine, nitrosamine ketone), polycyclic aromatic hydrocarbons, heavy metals (including organometal compounds) and aldehydes/other complex organic compounds. These arise both as constituents of the e-liquid (with many aldehydes and other complex organics used as flavourings) and as a result of pyrolysis/complex organic reactions in the electronic cigarette device (including unequivocal carcinogens such as formaldehydeformed from pyrolysis of glycerol). Various studies demonstrate in vitro transforming and cytotoxic activity of these derivatives. E-cigarette device use has been significantly increasingparticularly amongst the younger cohort and non-smokers; thus, this is an area of significant concern for the future. Conclusion: Although research remains somewhat equivocal, there is clear reason for concern regarding the potential oncogenicity of E-Cigarettes/E-Liquids with a strong basic and molecular science basis. Given lag times (extrapolating from tobacco smoke data) of perhaps 20 years, this may have significant future public health implications. Thus, the authors feel further study in this field is strongly warranted and consideration should be made for tighter control and regulation of these products.

Tobacco Smoke and Electronic Cigarette Vapor Alter Enhancer RNA Expression That Can Regulate the Pathogenesis of Lung Squamous Cell Carcinoma

“…In addition to investigating the impact of tobacco smoke on eRNA expression in LUSC, we also examined the effect of e-cigarette smoke on eRNA expression and immune cell abundance. E-cigarettes are commonly used to aid with smoke cessation and control [18,54]. However, there are concerns that e-cigarette smoke may be implicated in lung cancer [18].…”

“…E-cigarettes are commonly used to aid with smoke cessation and control [18,54]. However, there are concerns that e-cigarette smoke may be implicated in lung cancer [18]. E-cigarettes contain a myriad of carcinogenic substances, such as carbonyl compounds, which have the potential to cause DNA breaks and inhibit DNA repair [18].…”

“…For example, e-cigarette devices have various carbonyl compounds, such as acetaldehyde and formaldehyde, which have inflammatory and toxic effects. The inflammation induced by these particular substituents has been found to lead to the activation of macrophages and the generation of reactive oxidative species, which can result in greater immune modulation and induce the production of inverse inflammasomes [18]. As such, an immunosuppressive environment is created, with an increased hostility towards T cells, which is also commonly associated with lung cancer oncogenesis and malignancy.…”

“…Moreover, 10% of the nicotine substances in electronic cigarette devices undergo a conversion to nitrosamine, increasing the risk for nitrosamine carcinogenesis. Previous studies have found that nitrosamine carcinogenesis is caused by increased DNA methylation and agonistic activity on the nicotinic acetylcholine receptor, which promotes tumor growth [18]. E-cigarettes have also been found to contain acrolein, a substance that is commonly associated with lung damage, chronic obstructive pulmonary disease (COPD), and lung cancer.…”

“…It is well established that cancer is a genetic disease associated with DNA alterations and mutations [17]. Accordingly, e-cigarettes contain various substituents, such as carbonyl compounds [18], acrolein [19], and nicotine substances [18], which are highly capable of causing DNA breakages, inhibiting DNA repair functions, and releasing reactive oxygen species [18]. As such, these substituents increase the risk for lung cancer and promote tumor growth.…”