Vitamin D3: an ever green molecule.

Department of Biomedical Sciences, University of Catania, Italy, Department of Experimental and Clinical Pharmacology, University of Catania, Italy, Department Of Pediatrics and Pediatric Neurology, Azienda Ospedaliera Universitaria OVEPoliclinico, University of Catania, Department of Medical Oncology, National Cancer Institute, Aviano (PN), Italy, Department of Medicine and Medical Specialties, Division of Infectious Diseases, University of Catania, Italy