These results show that G361 malignant melanoma cells have lost the ability to regulate the cell cycle at the G1/S checkpoint and are more sensitive than melanocytes to cell killing by UVC and UVB but not UVA radiation. Similarly, exposure of these melanoma cells to UVC and UVB, and to a much lesser extent UVA, induced chromatid aberrations. UVA nevertheless induced strong cell cycle delays in both cell types, indicating that UVA exposure can significantly affect genome metabolism.

There was no evidence of any photosensitizing effect of increased melanin on human melanoma cell survival following exposure to UVC, UVB or broadband UVA radiation. The slight protective effect seen following exposure to UVB radiation may have been due to increased scavenging of reactive-oxygen species, particularly by eumelanin, at this wavelength.