title: CYP1A1 gene polymorphisms as a risk factor for pterygium.
abstract: OBJECTIVE
  Both cytochrome P4501A1 (CYP1A1) and glutathione S-transferase M1 (GSTM1) have been demonstrated to be involved in the metabolism of polycyclic aromatic hydrocarbons (PAHs). BaP 7,8-diol 9,10-epoxide (BPDE), an ultimate metabolite of benzo(a)pyrene (BaP), attacks deoxyguanosine to form a BPDE-N2-dG adduct resulting in p53 gene mutations. Our previous report indicated that BPDE-like DNA adduct levels in pterygium were associated with CYP1A1 gene polymorphisms. Therefore, we hypothesize that the genetic polymorphisms of CYP1A1 and GSTM1 increase the risk for pterygium.
  
  
  METHODS
  Two hundred-five pterygial specimens and 206 normal controls were collected in this study. For the analysis of CYP1A1 and GSTM1 gene polymorphisms, DNA samples were extracted from blood cells and then subjected to restriction fragment length polymorphism and polymerase chain reaction for the determination of mutation and genotype of CYP1A1 and GSTM1.
  
  
  RESULTS
  There was a significant difference between the case and control groups in the CYP1A1 genotype (p=0.0161) but not in GSTM1 (p=1.000). The odds ratio of the CYP1A1 m1/m2 polymorphism was 1.327 (95% CI=0.906-2.079, p=0.135) and the m2/m2 polymorphism was 1.647 (95% CI=1.154-2.350, p=0.006), compared to the m1/m1 wild-type genotype. The GSTM1 polymorphisms did not have an increased odds ratio compared with the wild type.
  
  
  CONCLUSIONS
  In conclusion, a CYP1A1 polymorphism is correlated with pterygium and might become a marker for the prediction of pterygium susceptibility.
authors.affiliation: Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan.
authors.forename: Chi-Hsien
authors.initials: CH
authors.lastname: Young
authors.forename: Yu-Lun
authors.initials: YL
authors.lastname: Lo
authors.forename: Yi-Yu
authors.initials: YY
authors.lastname: Tsai
authors.forename: Tung-Sheng
authors.initials: TS
authors.lastname: Shih
authors.forename: Huei
authors.initials: H
authors.lastname: Lee
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Cheng
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011625:Pterygium / Q000235:genetics*
chemical_list: D019363:Cytochrome P-450 CYP1A1; D005982:Glutathione Transferase