Narrow-band UVB induces more carcinogenic skin tumors than broad-band UVB through the formation of cyclobutane pyrimidine dimer.
Phototherapy with narrow-band UVB (NB-UVB), with a peak exclusively at 311 nm wavelength, has been found to be more effective in treating a variety of skin diseases than conventional broad-band UVB (BB-UVB). To assess the difference in carcinogenic activity between NB-UVB and BB-UVB, we investigated skin tumor formation by irradiating albino hairless, Ogg1 knockout mice and C57BL/6J wild counterparts with these two UV sources. We found that the ratio of malignant skin tumors induced by NB-UVB was significantly higher than that induced by BB-UVB. There was no significant difference in carcinogenicity of skin tumor induced by NB-UVB between Ogg1 knockout and wild-type mice. To investigate the possible cause of different carcinogenic activity by the different UV sources, we examined three types of DNA damage: cyclobutane pyrimidine dimer (CPD), (6-4) photoproduct, and 8-oxoguanine (8-oxoG) induced by each UV source. We found that CPD formation following a minimum erythema dose (MED) by NB-UVB was significantly higher than that following 1 MED by BB-UVB, whereas the formation of (6-4) photoproducts and 8-oxoG following BB-UVB was significantly higher than those following NB-UVB exposure. These results suggest that CPD formation is closely related to the higher carcinogenic characteristics of NB-UVB. JID JOURNAL CLUB ARTICLE: For questions, answers and open discussion about this article please go to http://network.nature.com/.
Kunisada
Makoto
M
Division of Dermatology, Clinical Molecular Medicine, Faculty of Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Kumimoto
Hiroshi
H
Ishizaki
Kanji
K
Sakumi
Kunihiko
K
Nakabeppu
Yusaku
Y
Nishigori
Chikako
C
D000818:Animals; D002471:Cell Transformation, Neoplastic; D003503:Cyclobutanes / Q000737:chemistry*; D045647:DNA Glycosylases / Q000235:genetics*; D004817:Epidermis / Q000187:drug effects* / Q000528:radiation effects*; D006151:Guanosine / Q000031:analogs & derivatives / Q000737:chemistry; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010777:Photochemistry / Q000379:methods*; D011740:Pyrimidine Dimers / Q000737:chemistry*; D012878:Skin Neoplasms / Q000209:etiology*; D014466:Ultraviolet Rays
D003503:Cyclobutanes; D011740:Pyrimidine Dimers; D006151:Guanosine; C046215:8-hydroxyguanosine; D045647:DNA Glycosylases; C485990:Ogg1 protein, mouse