title: Polymorphism of SMAD7 gene (rs2337104) and risk of colorectal cancer in an Iranian population: a case-control study.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the influence of intronic polymorphism of the SMAD7 (Mothers Against Decantaplegic Homolog 7) gene (rs2337104) on the risk of colorectal cancer (CRC) and clinicopathological features in an Iranian population.
  
  
  BACKGROUND
  SMAD7 has been identified as an antagonist of transforming growth factor beta (TGF-b)-mediating fibrosis, carcinogenesis, and inflammation. Regarding to the recent genome-wide scan, a risk locus for colorectal cancer at 18q21 has been found, which maps to the SMAD7 gene.
  
  
  METHODS
  This case-control study was performed on 109 CRC patients and 109 healthy controls recruited in Taleghani Hospital. The genotyping of all samples were done by TaqMan assay via an ABI 7500 Real Time PCR System (Applied Biosystems) with DNA from peripheral blood. The association of this polymorphism with the risk of CRC and clinicopathological features was investigated.
  
  
  RESULTS
  Our results indicated that there were no significant association between genotypic and allelic frequencies of SMAD7 polymorphism (rs2337104) and CRC risk in our population. Although the T allele is the most frequent one in this population and its frequency was 86.7% in patients compared with 91.7% in controls (OR=1.705, 95% CI= 0.916-3.172). Also, the SMAD7 genotypes were not associated with any clinicopathological characteristics in CRC patients (P>0.05).
  
  
  CONCLUSIONS
  For the first time, this study results revealed that this SMAD7 polymorphism couldn't be a potential risk factor for CRC or a prognostic biomarker for prediction of clinicopathological features in an Iranian population. A large-scale case-control study is needed to validate our results.
authors.affiliation: Gastroenterology and Liver Diseases Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran ; Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Akbari
authors.affiliation: Proteomics Research Center, Faculty of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Nahid
authors.initials: N
authors.lastname: Safari-Alighiarloo
authors.affiliation: Gastroenterology and Liver Diseases Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Yaghoob
authors.initials: MY
authors.lastname: Taleghani
authors.affiliation: Gastroenterology and Liver Diseases Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Farzaneh Sadat
authors.initials: FS
authors.lastname: Mirfakhar
authors.affiliation: Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Asadzadeh Aghdaei
authors.affiliation: Gastroenterology and Liver Diseases Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Vahedi
authors.affiliation: Gastroenterology and Liver Diseases Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Atena
authors.initials: A
authors.lastname: Irani Shemirani
authors.affiliation: Gastroenterology and Liver Diseases Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Nazemalhosseini-Mojarad
authors.affiliation: Gastroenterology and Liver Diseases Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Zali
keywords: Colorectal cancer; SMAD7; Single nucleotide polymorphism (SNP)