title: The synergy of tobacco and alcohol and glutathione S-transferase θ 1 gene deletion and oral squamous cell carcinoma.
abstract: BACKGROUND
  Oral squamous cell carcinoma (OSCC) is the leading cancer among males in India. It is related to tobacco habits and alcohol consumption as well as the individual susceptibility for xenobiotic metabolizing enzyme polymorphisms. Glutathione S-transferase θ 1 (GSTT1) is a Phase II metabolic enzyme which is directly involved in catalyzing chemicals to mutagenic intermediates. This gene is characterized by genetic polymorphism resulting in complete gene deletion and subsequent absence of the enzyme, which ultimately dictates the risk of cancer development. Scraping buccal mucosa to obtain DNA from the cells is a simple, readily acceptable and rapid method to detect and assess the gene.
  
  
  OBJECTIVE
  To assess GSTT1 gene deletion in individuals giving a history of tobacco smoking and/or chewing and alcohol consumption and absence of clinically detectable lesions; and in OSCC cases to gauge if GSTT1 gene deletion confers protection to an individual and whether it can be used as a "single" marker to arrive at this conclusion. To validate the use of buccal scrape for determining the genotype of an individual by assessing the polymorphism at GSTT1 gene locus (22q11.2).
  
  
  METHODS
  Fifty-two cases were evaluated using buccal mucosal scrapes of tobacco habituates for 8 or more years, without clinically evident lesion (Group I) and from mucosa of tobacco habituates with clinically evident and histopathologically confirmed OSCC (Group II). DNA extraction and genotype at GSTT1 gene locus was determined by polymerase chain reaction assay.
  
  
  METHODS
  The results were statistically analyzed using Chi-square test.
  
  
  RESULTS
  90.66% of subjects had GSTT1 null genotype in Group I subjects. In Group II, subjects with both clinically and histopathologically diagnosed oral cancer, about 76.96% had GSTT1 null genotype.
  
  
  CONCLUSIONS
  GSTT1 null genotype confers protection to individuals with tobacco habits and alcohol consumption, predominantly to those who used chewable form of tobacco and especially among female population. However, the influence of many other environmental, genetic and epigenetic factors should be considered for the genesis/occurrence of cancer.
authors.affiliation: Private Dental Practitioner, Mumbai, Maharashtra, India.
authors.forename: Sarah
authors.initials: S
authors.lastname: D' Mello
authors.affiliation: Department of Oral Pathology, Krishnadevaraya College of Dental Sciences, Bengaluru, Karnataka, India.
authors.forename: Radhika Manoj
authors.initials: RM
authors.lastname: Bavle
authors.affiliation: Department of Oral Pathology, Krishnadevaraya College of Dental Sciences, Bengaluru, Karnataka, India.
authors.forename: K
authors.initials: K
authors.lastname: Paremala
authors.affiliation: Department of Oral Pathology, Krishnadevaraya College of Dental Sciences, Bengaluru, Karnataka, India.
authors.forename: Soumya
authors.initials: S
authors.lastname: Makarla
authors.affiliation: Department of Oral Pathology, Krishnadevaraya College of Dental Sciences, Bengaluru, Karnataka, India.
authors.forename: M
authors.initials: M
authors.lastname: Sudhakara
authors.affiliation: Private Dental Practitioner, Bengaluru, Karnataka, India.
authors.forename: Madhura
authors.initials: M
authors.lastname: Bhatt
keywords: Alcohol; buccal scrapes; glutathione S-transferase θ 1 gene; oral squamous cell carcinoma; tobacco habits