Background: Squamous cell carcinoma (SCC) is linked with the lifelong cumulative effect of ultraviolet radiation (UVR). In contrast, epidemiological data have shown that sunburn in childhood is a stronger risk factor for cutaneous malignant melanoma than continuous UVR, indicating a higher carcinogenic sensitivity early in life.
Methods: We investigated how a high neonatal dose of UVR affects the development of SCC in mice irradiated later in life. We used simulated solar radiation (sun) and solarium radiation (solarium). Ninety-nine C3.Cg/TifBomTac-immunocompetent hairless mice received 0, 25 or 35 standard erythema doses (SED) UVR when they were 4 days old followed by 4 SED sun or 4 SED solarium three times/weekly from 9 weeks of age.
Results: Tumours developed faster in mice treated with 35 SED UVR + 4 SED sun compared with 4 SED sun, but no change was observed in the cumulative dose required to achieve tumours. Tumours also developed faster in mice treated with 35 SED UVR + 4 SED solarium compared with 4 SED solarium, and a difference was also observed in the cumulative dose required to achieve tumours. If the Skin Cancer Utrecht-Philadelphia-murine spectrum was used to weigh the delivered irradiance instead of the International Commission on Illumination erythema action spectrum, tumours developed after the same accumulated dose.
Conclusion: In conclusion, this study does not indicate increased sensitivity to induction of SCC early in life.
© 2012 John Wiley & Sons A/S.