The radioactive substances in tobacco leaves occurring tobacco-related cancers: A review

Introduction: The presence of naturally radioactive substances in tobacco leaves occurring radionuclides, suchas Radium-۲۲۶ (۲۲۶Ra), Actinium-۲۲۸ (۲۲۸Ac), Bismuth-۲۱۴ (۲۱۴Bi), and Radium-۲۲۸ (۲۲۸Ra), originate from soiland fertilizers which is used in tobacco growing. They increase internal absorption and radiation dose whentobacco smoking. Additionally, other radioactive elements such as lead-۲۱۰ (۲۱۰Pb) and polonium-۲۱۰ (۲۱۰Po)are found in tobacco due to their presence in phosphate-rich fertilizers and natural soils. The aim of this studyis to evaluate the mechanism of radioactive substances in tobacco leaves occurring tobacco-related cancers.Methods: In this review article, using keywords including natural radioactivity, tobacco, cancer development,cigarette, smoking, cancer, and carcinogenesis in the title and abstract. Articles were collected from Medline,PubMed, Scopus, and Google Scholar search engines. Articles were searched without a time limit. Inclusioncriteria included being written in English and having full-text availability.Results: The radioactive substances in tobacco leaves promote tumor growth by enhancing and disrupting cellproliferation, survival, migration, and invasion, thereby creating a microenvironment conducive to tumorgrowth. Tobacco products contain many chemical carcinogens including tobacco-specific nitrosamines such asNNK and NNN. Also, tobacco products contain many radioactive substances including, Radium-۲۲۶ (۲۲۶Ra),Actinium-۲۲۸ (۲۲۸Ac), Bismuth-۲۱۴ (۲۱۴Bi), and Radium-۲۲۸ (۲۲۸Ra). One way these nitrosamines andradioactive substances contribute to cancer is through causing oxidative stress. Oxidative stress occurs whenthe production of oxidants exceeds the cell's neutralizing capacity.Conclusion: The presence of radioactive elements in tobacco and exposure during smoking contributesignificantly to the development of tobacco-related cancers. This highlights the urgent need for effective tobaccocontrol measures to reduce the cancer burden. The carcinogenic mechanism of tobacco is very diverse andcomplex, involving both chemical and radiobiological factors. Understanding these mechanisms can helpdevelop sensitive methods to identify signature carcinogens in tobacco, facilitating effective and targetedepidemiological studies.

کلیدواژه ها:

natural radioactivity ، tobacco ، cancer development ، cigarette ، smoking ، and cancer