Molecular insights into the role of electronic cigarettes in oral carcinogenesis

Abstract

Electronic cigarette (EC) usage or vaping has seen a significant rise in recent years across various parts of the world. They have been publicized as a safe alternative to smoking; however, this is not supported strongly by robust research evidence. Toxicological analysis of EC liquid and aerosol has revealed presence of several toxicants with known carcinogenicity. Oral cavity is the primary site of exposure of both cigarette smoke and EC aerosol. Role of EC in oral cancer is not as well-researched as that of traditional smoking. However, several recent studies have shown that it can lead to a wide range of potentially carcinogenic molecular events in oral cells. This review delineates the oral carcinogenesis potential of ECs at the molecular level, providing a summary of the effects of EC usage on cancer therapy resistance, cancer stem cells (CSCs), immune evasion, and microbiome dysbiosis, all of which may lead to increased tumor malignancy and poorer patient prognosis. This review of literature indicates that ECs may not be as safe as they are perceived to be, however further research is needed to definitively determine their oncogenic potential.

Keywords:

• E-cigarettes (ECs)
• vaping
• oral cancer
• carcinogenesis
• oral microbiome
• immune surveillance
• therapy resistance

Acknowledgments

The authors gratefully acknowledge Dr. Srikumar Chellappan, former chair and senior member of Department of Tumor Biology at H. Lee Moffitt Cancer Center, Tampa, USA for reviewing the manuscript and his insightful comments. The authors also extend their gratitude to Editor-in-Chief, Dr Roger McClellan and the anonymous reviewers selected by the editor for their valuable comments which have helped improve our manuscript significantly.

Author contributions

Meenu Maan: Study conceptualization and design, Writing: original draft, Revision: Addressing reviewer and editor comments; Moosa Abuzayeda: Study conceptualization and design, Writing: review and editing; Eleftherios G. Kaklamanos: Study conceptualization and design, Writing: review and editing; Mohamed Jamal: Study conceptualization and design, Writing: review and editing; Mainak Dutta: Study conceptualization and design, Writing: original draft; Keyvan Moharamzadeh: Study conceptualization and design, Writing: review and editing, Revision: Addressing reviewer and editor comments.

Declaration of interest

This review aims to provide a detailed analysis of the current understanding of the oncogenic potential of e-cigarettes in oral cancer. It delineates the effects of EC usage on host immune surveillance, CSCs, oral microbiome dysbiosis and anti-cancer therapy resistance. The authors believe that it will fill an important gap in the current understanding of the oral oncogenic potential of ECs. This review was made possible by the funding from Hamdan Bin Mohammed College of Dental Medicine (HBMCDM), Mohammed Bin Rashid University of Medicine and Health Sciences (MBRU) Dubai, UAE (Internal Research Grant Number: MBRU-HBMCDM-RG2020-01). The authors have not participated in, nor anticipate to participate in, any legal, regulatory, or advocacy proceedings related to the contents of this manuscript. The authors bear sole responsibility for the preparation of this article and the opinions and conclusions given here are their own and not necessarily shared by the funding agency. The author affiliations are as shown on the cover page. The authors have no conflict of interest to disclose.