Haplotype Analysis of Vitamin D Receptor (VDR) Gene in Breast Cancer Patients

Background: The aim of the study was to evaluate the role of well-characterized vitamin D receptor (VDR) gene polymorphisms, BsmI (rs 1544410), ApaI (rs 7975232), TaqI (rs 731236), and FokI (rs 10735810) and their haplotypes in the pathogenesis of breast cancer in Turkish women. Methods: The subjects consisted of women including 331 breast cancer patients and 345 healthy controls. After conventional DNA isolation genotyping was done by a PCR-RFLP method, haplotype analysis was performed using Haploview 4.2. Results: Haplotype analysis in different combinations revealed that frequencies of Fbt, fbt, bAt, and bt haplotypes are significantly higher in breast cancer patients than controls (chi(2) = 6.862, p = 0.0088; chi(2) = 4.176, p = 0.041; chi(2) = 4.184, p = 0.0408; chi(2) = 8.409, p = 0.0037 respectively). However, no statistically significant difference between genotypes of cases and controls were found when analyzed separately. Conclusions: All these data support the hypothesis that it is crucial to evaluate VDR gene polymorphism by haplotype analysis in order to understand how changes in VDR sequence influence the function of the VDR gene and how this variability affects the risk of breast cancer.