The potential role of peroxisome-proliferator activated receptor (PPAR) ligands and 1,25 (OH)2D3 in melanoma cell activity was investigated. Antiproliferative effects of various PPAR-ligands and 1,25(OH)2D3 on melanoma cell lines were found in terms of PPAR and VDR expression. PPAR and VDR expression are likely interconnected and may be involved in the pathogenesis, progression and therapy of malignant melanoma (MM) (Sertznig, P. et al. Exptl Dermatol 2008, 17( 7): 626-627). An investigation of the correlation between serum 25-hydroxy vitamin D (25-OHD) with the temporal course of melanoma progression was conducted. Data from 212 patients with acute cutaneous MM (stages 1-IV) were compared with a control group (n=80). Basal 25-OHD levels were nonsignificantly lower in the control ...