This will be the first study designed to evaluate the possible role of individual polymorphisms in VDR and to conduct an extensive analysis of VDR haplotypes on different aspects of responses of breast cancer survivors, i.e., inflammatory, oxidative stress, and metabolic biomarkers, biomarkers associated with cell proliferation, differentiation, damage, apoptosis, and anthropometric measures to daily supplementation of 4000 international unit (IU) vitamin D for 12 weeks. Here, VDR is linked to breast cancer.