title: Effect of ultraviolet (UV) radiation and UVB-absorbing sunscreen ingredients on 7,12-dimethylbenz(a)anthracene-initiated skin tumorigenesis in hairless mice.
abstract: These experiments describe the enhancement of 7,12-dimethylbenz(a)anthracene (DMBA)-initiated skin tumorigenesis in hairless mice by subsequent chronic ultraviolet (UV) irradiation of the same skin site. Each carcinogen was administered at a level that separately resulted in threshold tumorigenesis. The cocarcinogenic response was evident as a marked increase in tumour incidence, tumour multiplicity and degree of tumour malignancy. Irradiation through the topically applied UVB (290-315 nm)-absorbing sunscreen ingredient, 2-ethylhexyl-p-methoxycinnamate, totally protected from the photoenhancement. However, irradiation through an alternative UVB absorber, octyl-N-dimethyl-p-aminobenzoate, failed to protect from photoenhancement. A possible immunologic role for the enhancement of DMBA tumorigenesis by UV radiation is proposed.
authors: Department of Veterinary Pathology, University of Sydney, New South Wales, Australia.
authors: V E
authors: VE
authors: Reeve
authors: M
authors: M
authors: Bosnic
authors: C
authors: C
authors: Boehm-Wilcox
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000279:Administration, Cutaneous; D000818:Animals; D003043:Cocarcinogenesis; D005260:Female; D051379:Mice; D008812:Mice, Hairless; D012867:Skin / Q000528:radiation effects*; D012878:Skin Neoplasms / Q000139:chemically induced*; D013473:Sunscreening Agents; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D013473:Sunscreening Agents; D015127:9,10-Dimethyl-1,2-benzanthracene