Review Article http://doi.org/10.18231/j.idjsr.2019.022 International Dental Journal of Student Research, October-December, 2019;7(4):84-86 84 Pathogenesis of oral squamous cell carcinoma- An update C Gayathri 1* , M Sivaramakrishnan 2 , R Suganya 3 , A Santhadevy 4 , N Vezhavendhan 5 1 Post Graduate, 2,3 Reader, 4 Professor and Head, 5 Professor, Dept. of Oral & Maxillofacial Pathology & Oral Microbiology, Indira Gandhi Institute of Dental Sciences, Sri Balaji Vidyapeeth (Deemed to be university), Puducherry, India *Corresponding Author: C Gayathri Email: gayathri02.bds@gmail.com Abstract Oral cancer is the sixth most common malignancy in the world. Oral cancer is of major concern in Southeast Asia primarily because of the deleterious habits such as smoking, betel nut chewing and alcohol consumption. Despite recent advances in cancer diagnoses and therapies, the survival rate of oral cancer patients has remained at a dismal 50% in the last few decades. This paper is an overview of the various etiological agents and risk factors implicated in the development of oral cancer. Keywords: Tobacco, Alcohol, Squamous cell carcinoma, Risk factors. Introduction Oral squamous cell carcinoma in India ranks first among male and third among female. 1 Oral carcinoma is a multistep process develops by genetic alterations, genetic predisposition, environmental influences such as tobacco, alcohol, chronic inflammation, viral infections, Diet and nutrition, Fungal infections, Dental factors, Trauma, Age, Immune suppression. 2 Certain etiological factors such as tobacco and alcohol consumption is well established, however 15 to 20% oral cancer develops in patients without this habits. 3 This paper is an overview of etiological factors and molecular changes in development of oral squamous cell carcinoma. Etiological Factors Tobacco The carcinogen in tobacco causes DNA adducts. This DNA adducts found to play main role in chemical carcinogenesis. If this DNA adducts are repaired by DNA repair pathways, they revert back to normal state. An important thing to be noted is metabolic activation varies between individuals such as genetic polymorphism in carcinogen. Metabolism of gene is an important determinant of DNA adducts levels, also it helps in identification of smokers with increased risk for cancers. More than 90% of oral squamous cell carcinoma has been reported because of tobacco habits. 4 The flow chart depicts the role of tobacco and its carcinogens in development of oral squamous cell carcinoma. 5 Alcohol The carcinogens that are present in the alcohol has been implicated in development of oral cancer. Consumption of alcohol and tobacco found to act synergistically and pave way in development of oral cancer. In few studies alcohol itself is found to be an independent risk factor in development of oral epithelial dysplasia and oral cancer. 6 Alcohol leads to increase permeability of oral mucosa, causing alteration in morphology, characterized by epithelial atrophy, leading to easier penetration of carcinogen in the oral mucosa. 5