<unk>  squamous cell carcinoma is a disease of environmental factors, the greatest of which is tobacco. Like all environmental factors, the rate at which<unk>  will develop is dependent on the dose, frequency and method of application of the carcinogen (the substance that is causing the<unk> . Aside from cigarette smoking, other carcinogens for<unk>  include alcohol, viruses (particularly HPV 16 and 18), radiation, and UV light. Tobacco Tobacco is the greatest single cause of<unk>  and pharyngeal<unk> . It is a known multi-organ carcinogen, that has a synergistic interaction with alcohol to cause<unk> s of the mouth and pharynx by directly damaging cellular DNA. Tobacco is estimated to increase the risk of<unk>  by 3.4–6.8 and is responsible for approximately 40% of all<unk> s. Alcohol Some studies in Australia, Brazil and Germany pointed to alcohol-containing mouthwashes as also being potential causes. The claim was that constant exposure to these alcohol-containing rinses, even in the absence of smoking and drinking, leads to significant increases in the development of<unk> . However, studies conducted in 1985, 1995, and 2003 summarize that alcohol-containing mouth rinses are not associated with<unk> . In a March 2009 brief, the American Dental Association said "the available evidence does not support a connection between<unk>  and alcohol-containing mouthrinse". A 2008 study suggests that acetaldehyde (a breakdown product of alcohol) is implicated in<unk> , but this study specifically focused on abusers of alcohol and made no reference to mouthwash. Human papillomavirus Infection with human papillomavirus (HPV), particularly type 16 (there are over 180 types), is a known risk factor and independent causative factor for<unk> . A fast-growing segment of those diagnosed does not present with the historic stereotypical demographics. Historically that has been people over 50, blacks over whites 2 to 1, males over females 3 to 1, and 75% of the time people who have used tobacco products or are heavy users of alcohol. This new and rapidly growing subpopulation between 30 and 50 years old, is predominantly nonsmoking, white, and males slightly outnumber females. Recent research from multiple peer-reviewed journal articles indicates that HPV16 is the primary risk factor in this new population of<unk>  victims. HPV16 (along with HPV18) is the same virus responsible for the vast majority of all cervical<unk> s and is the most common sexually transmitted infection in the US.<unk>  in this group tends to favor the tonsil and tonsillar pillars, base of the tongue, and the oropharynx. Recent data suggest that individuals who develop the disease from this particular cause have a significant survival advantage, as the disease responds better to radiation treatments than tobacco caused disease. Betel nut Stall selling betel quid Chewing betel, paan and Areca is known to be a strong risk factor for developing<unk>  even in the absence of tobacco. It increases the rate of<unk>  2.1 times, through a variety of genetic and related effects through local irritation of the mucous membrane cells, particularly from the areca nut and slaked lime. In India where such practices are common,<unk>  represents up to 40% of all<unk> s, compared to just 4% in the UK. Stem cell transplantation People after hematopoietic stem cell transplantation (HSCT) are at a higher risk for<unk>  squamous cell carcinoma. Post-HSCT<unk>  may have more aggressive behavior with poorer prognosis, when compared to<unk>  in people not treated with HSCT. This effect is supposed to be owing to the continuous lifelong immune suppression and chronic<unk>  graft-versus-host disease. Premalignant lesions<unk>  leukoplakia (white patch) on the left tongue. Proven to be severe dysplasia on biopsy A premalignant (or precancerous) lesion is defined as "a benign, morphologically altered tissue that has a greater than normal risk of malignant transformation." There are several different types of premalignant lesion that<unk> cur in the mouth. Some<unk> s begin as white patches (leukoplakia), red patches (erythroplakia) or mixed red and white patches (erythroleukoplakia or "speckled leukoplakia"). Other common premalignant lesions include<unk>  submucous fibrosis and actinic cheilitis. In the Indian subcontinent<unk>  submucous fibrosis is very common due to betel nut chewing. This condition is characterized by limited opening of mouth and burning sensation on eating of spicy food. This is a progressive lesion in which the opening of the mouth becomes progressively limited, and later on even normal eating becomes difficult.
Oral cancer
Squamous cell carcinoma
Skin cancer
Head and neck cancer
Laryngeal cancer
Dental abscess
Salivary gland disease
Mouth ulcer