The Tumor Suppressor Actions of the Vitamin D Receptor in Skin

The study investigated the role of the vitamin D receptor (VDR) in skin tumor suppression, particularly in mice lacking VDR, which were prone to tumor formation when exposed to chemicals or UVB. The research focused on the activation of the hedgehog (HH) and wnt-catenin pathways in VDR null mice, which are known to promote cell proliferation and inhibit differentiation. To explore this, researchers developed genetically modified mice with alterations in the wnt-catenin and HH pathways and observed their effects on tumor development. The study found that even with the deletion of the catenin gene, which was expected to offer protection, tumors still developed in the VDR-catenin knockout mice. The research also noted disruptions in hair follicles and hair cycling, although some results, particularly the acute response to UVB, were still pending at the time.