title: Vitamin D and estrogen receptor gene polymorphisms and the risk of colorectal cancer in Bulgaria.
abstract: OBJECTIVE
  Different epidemiological studies report the protective effect on colorectal cancer (CRC) exerted by vitamin D(3) intake, estrogen replacement therapy, and increase of the risk of microsatellite instability (MSI) in CRC by withdrawal of estrogens. The aim of our study was to search for association between CRC and polymorphisms in estrogen receptor-alpha (ER-alpha) and Vitamin D receptor (VDR) genes.
  
  
  METHODS
  We analyzed the PvuII and XbaI polymorphisms from the ER-alpha gene and the BsmI polymorphism of the VDR gene in 140 patients with CRC (subsequently divided according to their MSI status) and 94 controls.
  
  
  RESULTS
  We have demonstrated that the presence of the PvuII pp genotype increased the risk of developing MSI(+) tumors about three times compared to MSI(-) tumors [odds ratio (OR)=3.09, 95% confidence interval (CI) 0.88-10.91]. The effect of the XbaI xx genotype was similar (OR=2.08, 95% CI 0.49-8.81). Our results for the VDR BsmI polymorphism showed an increased risk for CRC in bb carriers (OR=1.8, 95% CI 0.81-4.05).
  
  
  CONCLUSIONS
  We conclude that PvuII and XbaI polymorphisms in the ER-alpha gene were associated with the risk of developing MSI in CRC patients. The BsmI polymorphism in the VDR gene was linked to the risk of developing CRC.
authors.affiliation: Laboratory of Molecular Pathology, University Hospital of Obstetrics and Gynecology, Maichin Dom, 2 Zdrave street, Sofia 1431, Bulgaria. alextanya@excite.com
authors.forename: Tanya
authors.initials: T
authors.lastname: Kadiyska
authors.forename: Toma
authors.initials: T
authors.lastname: Yakulov
authors.forename: Radka
authors.initials: R
authors.lastname: Kaneva
authors.forename: Dimitar
authors.initials: D
authors.lastname: Nedin
authors.forename: Alexandrina
authors.initials: A
authors.lastname: Alexandrova
authors.forename: Antonina
authors.initials: A
authors.lastname: Gegova
authors.forename: Alexey
authors.initials: A
authors.lastname: Savov
authors.forename: Vanio
authors.initials: V
authors.lastname: Mitev
authors.forename: Ivo
authors.initials: I
authors.lastname: Kremensky
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002031:Bulgaria / Q000453:epidemiology; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000235:genetics*; D015252:Deoxyribonucleases, Type II Site-Specific; D047628:Estrogen Receptor alpha / Q000235:genetics*; D015914:Estrogen Replacement Therapy; D005260:Female; D005838:Genotype; D006801:Humans; D053842:Microsatellite Instability; D008875:Middle Aged; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D012306:Risk; D014807:Vitamin D / Q000235:genetics*
chemical_list: D047628:Estrogen Receptor alpha; D014807:Vitamin D; C025580:endodeoxyribonuclease XBAI; C025630:CAGCTG-specific type II deoxyribonucleases; D015252:Deoxyribonucleases, Type II Site-Specific