VDR and melanoma: VDR is an evolutionarily conserved member of the hormone-responsive NHR superfamily, expressed in malignant specimens (e.g. carcinomas and melanomas) and numerous mammalian tissues and, most crucially for our study, in bone and skin where it can be detected in a variety of cell types, including keratinocytes, fibroblasts, Langerhans cells, melanocytes, endothelial cells, and B- and T-lymphocytes [20,21].