Study Shows Cigarette Smoke Harms DNA More Than Previously Thought

In a peer reviewed study published in Plos|One Journal, scientists conclude that there is significant harm, worse than previously thought, to the DNA from cigarette smoke.  This study further confirms that the harm from cigarette smoke, with over 70 known carcinogens, can be enormously more harmful than e-cigarette vapors as concluded recently by Public Health England (e-cigarettes are around 95% less harmful than smoking)

 

Summary Below – click here for full article

Lung cancer is a deadly disease and a leading cause of cancerrelated mortality in the US and in the world [1–3]. In 2012, the most recent year data is available, lung cancer accounted for 1.8 million cases of cancer and 1.6 million deaths worldwide [4, 5].

Exposure to tobacco smoke is the predominant risk factor for the development of lung cancer and it is estimated to account for 85– 90% of all lung cancer cases [6, 7]. It is also associated with the formation of tumors at additional sites in the body that are not directly exposed to smoke including the bladder, pancreas, liver, stomach and bone marrow [8, 9]. Tobacco use remains prevalent in certain regions of the world [10] and while its use has declined in the US, approximately 50% of newly diagnosed lung cancers occur in former smokers [6]. Hence, lung cancer and other forms of cancer associated with tobacco smoke exposure remain a tremendous health burden in the US and worldwide. Continued elucidation of the molecular mechanisms that lead to the formation of cancers associated with tobacco smoke is essential for prevention, treatment and identification of individuals who are at greatest risk for the development of cancer.

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Thousands of compounds have been identified in the vapor and particulate phases of cigarette smoke and they include carcinogens, co-carcinogens, mutagens and tumor promoters. Approximately 70 of these compounds have been classified as carcinogens [7, 11].

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Discussion

In this study, we find that cigarette smoke condensate, a surrogate for tobacco smoke exposure, can inhibit NER function and reduce the expression of XPC, a key protein required for DNA damage recognition in the NER pathway. Consequently tobacco smoke exposure can affect the integrity of DNA in two fundamentally different ways. It is well established that it can introduce DNA damage, an important contributor to lung carcinogenesis. However, our findings indicate that, in addition, it can also inhibit the DNA repair pathway that is essential for the removal of some of the carcinogenic DNA damage introduced by smoke carcinogens. Hence, cells of the lung exposed to smoke would likely suffer an even greater DNA damage burden than previously held.

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