目的　研究维生素 D受体基因的多态性与乳腺癌的关系。方法　收集 86例乳腺癌患者及134名对照 ,用聚合酶链反应 -限制性片段长度多态性方法 ,在维生素 D受体基因的 3′端分析了两个限制性酶切位点 (Apa 及 Taq )的多态分布。结果　发现 Taq 位点等位基因在两个群体间分布的差异有显著性 (P=0 .0 0 0 4)。进一步对基因型进行分析发现 ,Tt、tt基因型与乳腺癌相关。而 Apa 位点两等位基因未发现在两群体中存在差异。对 Apa 及 Taq 两座位的单体型进行分析 ,发现 t A间存在连锁不平衡。在两群体中分析单体型的分布发现 t A在病例中的比例明显高于对照人群 ,提示 t A单体型与乳腺癌相关。两个位点等位基因及单体型与临床指标的分析均未发现阳性结果。结论　维生素 D受体基因的多态性与乳腺癌有关 ,提示维生素 D受体基因与乳腺癌有关 Objective To study the relationship between vitamin D receptor gene polymorphism and breast cancer. Methods Eighty-six breast cancer patients and 134 controls were enrolled. Two restriction enzyme sites were analyzed at the 3′ end of the vitamin D receptor gene by polymerase chain reaction-restriction fragment length polymorphism (Apa and Polymorphic distribution of Taq). Results The Taq locus allele was found to have a significant difference between the two populations (P=0.040). Further analysis of the genotypes revealed that the Tt and tt genotypes are associated with breast cancer. The two alleles at the Apa loci were not found to differ between the two populations. Analysis of the haplotypes of the Apa and Taq loci revealed a linkage disequilibrium between tA. Analysis of the distribution of haplotypes in both populations revealed that the proportion of tA in the cases was significantly higher than that of the control population, suggesting that the tA haplotype is associated with breast cancer. No positive results were found in the analyses of alleles, haplotypes, and clinical parameters at the two loci. Conclusion Vitamin D receptor gene polymorphism is associated with breast cancer, suggesting that vitamin D receptor gene is associated with breast cancer