title: P21(waf1/cip1) gene polymorphisms and possible interaction with cigarette smoking in esophageal squamous cell carcinoma in northeastern Iran: a preliminary study.
abstract: BACKGROUND
  The incidence of esophageal squamous cell carcinoma (ESCC) is very high in northeastern Iran. However, the genetic predisposing factors to ESCC in this region have not been clearly defined. The P21(waf1/cip1) gene is involved in the arrest of cellular growth, as induced by the p53 tumor suppressor gene. Two polymorphisms of p21 gene in codon 31 (p21 C98A, dbSNP rs1801270) and the 3'UTR (p21 C70T, dbSNP rs1059234) may affect protein expression and play a role in cancer susceptibility. The present study aimed to investigate the association of p21 polymorphisms in codon 31 and the 3'UTR, and cigarette smoking on the risk of ESCC in northeastern Iran.
  
  
  METHODS
  A case-control study was carried out to detect the p21 polymorphism in the 3'UTR and codon 31 of samples from 126 ESCC cases and 100 controls from 2006 to 2007. There were no significant differences of age and sex between cases and controls. Genotyping of p21 polymorphisms were determined with the PCR-RFLP method. Conditional logistic regression was used to adjust for potential confounders.
  
  
  RESULTS
  None of the p21 genotypes were significantly associated with risk of ESCC, even after adjusting for age and gender (P=0.52, OR=1.24; 95%CI: 0.63-2.42). However, the presence of these polymorphisms in combination with cigarette smoking had a synergistic interaction in ESCC carcinogenesis in northeastern Iran (P=0.02, OR=8.38; 95%CI: 1.03-67.93).
  
  
  CONCLUSIONS
  Our data suggests that these two p21 polymorphisms, both alone and in combination, are not genetic susceptibility biomarkers for ESCC. However, their interaction with cigarette smoking may influence the susceptibility to ESCC development in northeastern Iran.
authors.affiliation: National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.
authors.forename: Noushin
authors.initials: N
authors.lastname: Taghavi
authors.forename: Firouzeh
authors.initials: F
authors.lastname: Biramijamal
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Abbaszadegan
authors.forename: Hooman
authors.initials: H
authors.lastname: Khademi
authors.forename: Masoud
authors.initials: M
authors.lastname: Sotoudeh
authors.forename: Shahrouz
authors.initials: S
authors.lastname: Khoshbakht
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D016022:Case-Control Studies; D015897:Comorbidity; D016001:Confidence Intervals; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics*; D004938:Esophageal Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D005838:Genotype; D006801:Humans; D015994:Incidence; D007492:Iran / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D012016:Reference Values; D018570:Risk Assessment; D012907:Smoking / Q000453:epidemiology / Q000235:genetics*
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21