title: Vitamin D Receptor Poly(A) Microsatellite Polymorphism and 25-Hydroxyvitamin D Serum Levels: Association with Susceptibility to Breast Cancer.
abstract: OBJECTIVE
  According to previous studies, vitamin D exhibits protective effects against breast cancer via the vitamin D receptor (VDR). There is growing evidence that breast cancer incidence is associated with various polymorphisms of the VDR gene. This study investigates the association of VDR poly(A) microsatellite variants with 25-hydroxyvitamin D (25(OH)D) serum levels and breast cancer risk.
  
  
  METHODS
  Polymorphism analysis was performed on a total of 261 blood samples, which were collected from 134 women with breast cancer and 127 controls. Single strand conformation polymorphism was assessed by polymerase chain reaction in combination with sequencing to detect poly(A) lengths for each sample. The vitamin D levels of samples were determined by electrochemiluminescence.
  
  
  RESULTS
  The poly(A) variant L allele frequency was significantly higher in cancer patients than in controls (odds ratio [OR], 1.73; 95% confidence interval [CI], 1.16-2.57; p=0.006). Thus, carriers of the L allele (LS and LL genotypes) have a higher risk for breast cancer (OR, 1.86; 95% CI, 1.13-3.05; p=0.013). A larger increase in the risk for breast cancer was found in individuals with the L carrier genotype and lowered 25(OH)D levels.
  
  
  CONCLUSIONS
  The results primarily suggest that VDR gene polymorphism in the poly(A) microsatellite is associated with 25(OH)D levels and that it can affect the breast cancer risk in the female population from northern Iran.
authors.affiliation: Department of Molecular and Cell Biology, University of Mazandaran Faculty of Basic Sciences, Mazandaran, Iran.
authors.forename: Abasalt Hossienzadeh
authors.initials: AH
authors.lastname: Colagar
authors.affiliation: Department of Molecular and Cell Biology, University of Mazandaran Faculty of Basic Sciences, Mazandaran, Iran.
authors.forename: Hamid Moradi
authors.initials: HM
authors.lastname: Firouzjah
authors.affiliation: Department of Clinical Biochemistry, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Sohrab
authors.initials: S
authors.lastname: Halalkhor
keywords: 25-Hydroxyvitamin D 2; Breast neoplasms; Calcitriol receptors; Genetic polymorphism; Microsatellite repeats