tobacco, smoking, oral squamous cell carcinoma, carcinogenic pathways, Diseases of the respiratory system, RC705-779, Neoplasms. Tumors. Oncology. Including cancer and carcinogens, RC254-282

Introduction Tobacco is one of the most important risk factors for premature death globally. More than 60 toxic chemicals in tobacco can invade the body’s various systems. Oral squamous cell carcinoma (OSCC) is a pathological type of oral cancer, accounting for over 90% of oral cancers. A vast quantity of scientific, clinical and epidemiological data shows that tobacco is associated with the development of oral squamous cell carcinoma, and its carcinogenic pathways may be complicated. Methods We conducted a thorough electronic search by Cochrane, EMBASE and PubMed to identify relevant studies. Studies published up to the end of October 2018 were included. After assessing and selecting articles based on eligibility criteria, studies were classified and elaborated according to the pathogenesis. Results Tobacco as an important risk factor can cause epigenetic alteration of oral epithelial cells, inhibit multiple systemic immune functions of the host, and its toxic metabolites can cause oxidative stress on tissues and induce OSCC. In addition, some specific viruses such as EBV and HPV are thought to play a role in the development of OSCC. Conclusions Oral cancer ranks eighth among the most common causes of cancerrelated deaths worldwide, and tobacco is one the most important carcinogenic factors of OSCC. This review of the literature attempts to provide directions and ideas for future related research, and emphasizes the need for efforts to reduce tobacco consumption.