A synergistic action of 1α,25(OH)2D3 and rosiglitazone, a PPAR-γ ligand, has been shown during osteoblast-mediated mineralization (Woeckel et al., 2013a), while in human T47D breast cancer cells PPAR-γ binds VDR and represses its transcriptional activity, possibly also by competing for RXR heterodimerization (Alimirah et al., 2012). Here, VDR is linked to breast cancer.