Table 2.

Summary of established and presumed risk factors for Oral Cancer.

Precursor Conditions	Environmental Factors	Genetic Factors
Infections: HPV, EBV, HIV, Treponema pallidum and others (chronic Candidiasis ?)	Lifestyle (e.g., alcohol abuse, distilling cider, tobacco smoking/chewing, Betel quid or guṭkha chewing, marijuana (?), poor dental and oral hygiene)	Fanconi’s anemia
Chronic mouth’s irritation (aggressive mouthwashes, faulty dental prostheses, periodontal disease, gastro-esophageal reflux)	Low socio-economic status (poor or no access to oral health care facilities)	Hereditary genodermatoses (dyskeratosis congenita, xeroderma pigmentosum, scleroderma)
Immune suppression and immune disorders (i.e., trans-planted patients, due to the chronic inflammatory state associated with graft-versus host disease (GVHD)	Industrial pollution or occupational exposures (sulfuric acid, asbestos, formaldehyde, pyrene, methyl pyrene, leather and textile industries workers)	Plummer-Vinson (aka Patterson-Brown-Kelly) syndrome
	Dietary factors (deficiencies of vitamins A, E, B complex, zinc, low intake of fruit and vegetables, especially carrots, fresh tomatoes, and green peppers, manipulated aliments as fried foods)	Genetic polymorphisms of genes coding for enzymes (i.e., P450 and XMEs)
	Radiation exposure (UV-A, Ionizing radiation/radiation therapy)	Diabetes