title: Topical retinoic acid inhibits changes in Langerhans cell density during carcinogenesis.
abstract: Ultraviolet radiation (UVR), chemical carcinogens and contact sensitisers all reduce the density of Langerhans cells (LC) in murine epidermis; UVR also lowers the number of Thy-1 dendritic epidermal cells (Thy-1+ dEC). Topical application of all-trans retinoic acid (RA) renders these cells insensitive to UVR and the tumour promoter 12-0-tetradecanoylphorbol 13-acetate (TPA) but does not inhibit LC migration from the epidermis in response to a contact sensitiser. Additionally, when the diet of mice was supplemented with the retinoid temarotene, UVR was unable to reduce the number of LC or Thy-1+ dEC. Hence one of the anti-carcinogenic mechanisms of retinoids may be to protect LC from carcinogens.
authors.affiliation: Department of Dermatology, University of Sydney, Royal Prince Alfred Hospital, Camperdown, N.S.W., Australia.
authors.forename: G M
authors.initials: GM
authors.lastname: Halliday
authors.forename: D A
authors.initials: DA
authors.lastname: McKay
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D002452:Cell Count / Q000187:drug effects / Q000528:radiation effects; D002465:Cell Movement / Q000187:drug effects; D007801:Langerhans Cells / Q000166:cytology / Q000187:drug effects* / Q000528:radiation effects; D009374:Neoplasms, Experimental / Q000517:prevention & control*; D014212:Tretinoin / Q000008:administration & dosage*; D014466:Ultraviolet Rays
chemical_list: D014212:Tretinoin