Background: Vitamin D inhibits cell proliferation via the vitamin D receptor (VDR), which may affect breast cancer risk. This study aimed to investigate the association of ApaI and TaqI polymorphisms of the VDR gene with breast cancer risk which followed by stratified analysis.
Materials and methods: A case-control study was conducted on 150 breast cancer patients and 150 healthy controls. VDR ApaI and TaqI genotyping were performed by PCR-RFLP. Some demographic and pathologic features of patients were extracted from their archived files and then were analyzed by genotypes distributions.
Results: For ApaI polymorphism, our data showed a significant difference between the patient and healthy groups for mutant allele carriers compared with those with AA genotype. Besides, statistical analysis showed that there was a significant association between the C allele and the increased risk of breast cancer. For TaqI polymorphism, statistical analysis revealed that there was a significant association between CC genotype and increased risk of breast cancer. Also, there was a significant association between the C allele and the increased risk of breast cancer. In a preliminary study, stratified analysis based on the size of tumor and lymph node metastasis revealed no significant association between two ApaI and TaqI variations and these parameters.
Conclusions: Based on our results, the VDR ApaI and TaqI variations could be considered as genetic risk factors for breast cancer. However, further studies with a larger sample size are required to obtain more accurate outcomes, especially in stratified analysis.
Keywords: ApaI; Genetic polymorphism; TaqI; Vitamin D receptor; breast cancer.