A first approach to an action spectrum for 8-MOP phototumorigenesis in mice.

Groups of hairless albino mice were treated with 8-MOP and exposed to a fixed daily dose of UVR obtained from one of four different emission spectra. Each spectrum was obtained by filtering a xenon arc source with a different WG filter. The resultant spectra showed differences in their proportions of shorter UVA wavelengths. A decreased proportion of the shorter wave bands systematically increased the time to first tumor. These data suggest that the action spectrum for 8-MOP sensitized phototumorigenesis is similar to that of acute 8-MOP action spectra in mammalian skin, which usually show maximal activity in the 320-335 nm region.