Leukoplakia, OralLeukoplakiaLeukoplakia, HairyMouth NeoplasmsOral Submucous FibrosisMouth MucosaPrecancerous ConditionsTrypsin Inhibitor, Bowman-Birk SoybeanTobacco, SmokelessCarcinoma, Squamous CellMouth DiseasesArecaKeratosisLichen PlanusSmokingLichen Planus, OralTongueErythroplasiaCandidiasis, OralCarcinoma, VerrucousBiopsyCell Transformation, NeoplasticCytochrome P-450 CYP1A1Glutathione TransferaseHerpesvirus 4, Human