CYP27B1 and melanoma: As demonstrated in RT-PCR the panel of melanoma cell lines considered in this study invariably expressed VDR and the complete repertoire of transcripts that is required for vitamin D activation and catabolism, namely 25-hydroxylase (gene CYP27A1), 1α-hydroxylase (gene CYP27B1) and 24-hydroxylase (gene CYP24A1) (see supplementary Figure S2A).