VDR and neoplasm: Previous studies in skin suggest that the unliganded VDR plays a role in the context of normal keratinocyte stem cell function (through interaction with the canonical Wnt pathway).20,37,38 The fact that ablation of VDR expression in cancer cells results in a marked inhibition of cell and tumor growth raises the possibility of the unliganded VDR being involved in the regulation of cancer cell proliferation and apoptosis.