title: Manganese superoxide dismutase and catalase genetic polymorphisms, activity levels, and lung cancer risk in Chinese in Hong Kong.
abstract: BACKGROUND
  Antioxidants play an important role in counteracting the effects of potential carcinogens. We investigated the risk of lung cancer development with respect to manganese superoxide dismutase (MnSOD) and catalase genetic polymorphisms and their association with erythrocyte antioxidant activities.
  
  
  METHODS
  This was a case-control study involving patients with confirmed lung cancer and age-matched healthy controls. Genotyping of MnSOD and catalase in DNA extracted from peripheral white cells was performed by polymerase chain reaction-based restriction fragment length polymorphism. Erythrocyte superoxide dismutase and catalase activities were measured spectrophotometrically using chemical kinetic reactions.
  
  
  RESULTS
  We recruited 240 patients with lung cancer (63% male, aged 55.6 +/- 11.9 years, 58% adenocarcinoma, 85% clinical stage III or IV) and 240 age-matched healthy controls. The frequencies of the Val allele of MnSOD gene and the C allele of catalase gene were common (>86% and 90%, respectively), with similar distribution, in both patients with lung cancer and controls. The homozygous variant genotypes of MnSOD and catalase were not associated with increased lung cancer risk. The erythrocyte SOD and catalase activity was significantly lower among all patients with lung cancer as a whole compared with controls, irrespective of genotypes. However, patients with adenocarcinoma and non-adenocarcinoma showed differences in SOD and catalase activity among different genotypes in comparison with controls.
  
  
  CONCLUSIONS
  The common Val16Ala MnSOD polymorphism and C-T substitution in the promoter region of the catalase gene do not confer increased or reduced risk of lung cancer in Chinese in Hong Kong.
authors.affiliation: University Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong SAR, China.
authors.forename: James C
authors.initials: JC
authors.lastname: Ho
authors.forename: Judith C W
authors.initials: JC
authors.lastname: Mak
authors.forename: S P
authors.initials: SP
authors.lastname: Ho
authors.forename: Mary S M
authors.initials: MS
authors.lastname: Ip
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Tsang
authors.forename: W K
authors.initials: WK
authors.lastname: Lam
authors.forename: Moira
authors.initials: M
authors.lastname: Chan-Yeung
mesh_terms: D000230:Adenocarcinoma / Q000208:ethnology / Q000235:genetics*; D019943:Amino Acid Substitution; D044466:Asian People / Q000235:genetics*; D002374:Catalase / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000208:ethnology*; D005838:Genotype; D006801:Humans; D008175:Lung Neoplasms / Q000201:enzymology / Q000208:ethnology / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D013482:Superoxide Dismutase / Q000097:blood / Q000235:genetics* / Q000378:metabolism
chemical_list: D002374:Catalase; D013482:Superoxide Dismutase