title: Polymorphisms of glutathione-S-transferase genes and the risk of aerodigestive tract cancers in the Northeast Indian population.
abstract: BACKGROUND
  Widespread use of tobacco and betel quid consumption and a high incidence of tobacco-associated aerodigestive tract cancers have been reported in different ethnic groups from several regions of Northeast (NE) India. This study was done to explore the possibility of phase II metabolic enzymes being responsible for the high prevalence of cancers in this region of India.
  
  
  METHODS
  Samples from 370 cases with oral, gastric, and lung cancers and 270 controls were analyzed for polymorphism of glutathione-S-transferase (GST) genes using polymerase chain reaction-restriction fragment length polymorphism-based methods.
  
  
  CONCLUSIONS
  Tobacco smoking and betel quid chewing were found to be high risk factors for oral and lung cancers but not for gastric cancer, whereas tobacco chewing was found to be a risk factor for oral cancer but not for gastric or lung cancer. The variant genotypes of GSTP1 were not associated with any of the aerodigestive tract cancers. GSTT1 and GSTM1 null genotypes appeared to play a protective role for lung cancer (odds ratio [OR] = 0.47, 95% confidence interval [95% CI]: 0.24-0.93, p = 0.03) and (OR = 0.52, 95% CI: 0.28-0.96, p = 0.04), but they were not associated with oral and gastric cancers. However, when data was analyzed in different geographic regions the GSTT1 null genotype was found to be a significant risk factor for oral (OR = 2.58, 95% CI 1.01-6.61, p = 0.05) as well as gastric cancer (OR = 3.08, 95% CI 1.32-7.19, p = 0.009) in samples obtained from the Assam region of NE India. This is the first study on the association of GST polymorphisms and aerodigestive tract cancers in the high-risk region of NE India.
authors.affiliation: Institute of Pathology, Indian Council of Medical Research (ICMR), New Delhi, India.
authors.forename: Dhirendra Singh
authors.initials: DS
authors.lastname: Yadav
authors.forename: Thoudam Regina
authors.initials: TR
authors.lastname: Devi
authors.forename: Rakhshan
authors.initials: R
authors.lastname: Ihsan
authors.forename: Ashwani Kumar
authors.initials: AK
authors.lastname: Mishra
authors.forename: Mishi
authors.initials: M
authors.lastname: Kaushal
authors.forename: Pradeep Singh
authors.initials: PS
authors.lastname: Chauhan
authors.forename: Sarangadhara A R
authors.initials: SA
authors.lastname: Bagadi
authors.forename: Jagannath
authors.initials: J
authors.lastname: Sharma
authors.forename: Eric
authors.initials: E
authors.lastname: Zamoawia
authors.forename: Yogesh
authors.initials: Y
authors.lastname: Verma
authors.forename: Ambakumar
authors.initials: A
authors.lastname: Nandkumar
authors.forename: Sunita
authors.initials: S
authors.lastname: Saxena
authors.forename: Sujala
authors.initials: S
authors.lastname: Kapur
mesh_terms: D000230:Adenocarcinoma / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D000328:Adult; D000368:Aged; D001114:Areca / Q000009:adverse effects; D001711:Biotransformation; D002273:Carcinogens / Q000493:pharmacokinetics; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D051549:Glutathione S-Transferase pi / Q000235:genetics*; D005982:Glutathione Transferase / Q000235:genetics*; D006184:Habits; D006801:Humans; D007194:India / Q000453:epidemiology; D008175:Lung Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D015995:Prevalence; D012307:Risk Factors; D012959:Socioeconomic Factors; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D014026:Nicotiana
chemical_list: D002273:Carcinogens; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; C413545:glutathione S-transferase T1; C496556:GSTP1 protein, human