Fluorescent lighting enhances chemically induced papilloma formation and increases susceptibility to tumor challenge in mice.

To study whether fluorescent lighting at work might increase carcinogenesis, hairless mice were exposed to a bank of six 36 W standard fluorescent lamps (neutral-white) every workday for 8 h at an illuminance level of 1,000 lx. For comparison, other mice were exposed to UVB radiation or to simulated solar radiation. In experiment A the animals were irradiated for 6 weeks prior to the application of 7,12-dimethyl-benzanthracene once and--following an interval of 2 days--for 10 weeks after DMBA application. The number of blue nevi and papillomas was enhanced by exposure to all spectra 10 weeks after chemical tumor induction. In experiment B the animals were irradiated for 6 weeks prior to the transplantation of UV-induced fibrosarcoma cells from syngeneic mice into the dorsal and ventral skin. Within the following 4 months fibrosarcoma developed in the dorsal skin exposed to the fluorescent lighting and to the UVB radiation, as well as in the non-irradiated ventral skin of 10-20% of the mice. The results suggest that fluorescent lighting as used in certain work environments may increase carcinogenesis caused by other factors.