Interesting. I'm seeing a number of warnings about the risks of shellac / gel nail polish and the associated UV exposure, but this article says:
Unlike melanoma of the skin, ultraviolet radiation exposure is likely not an important risk factor for nail melanoma. The two main risk factors for nail melanoma are previous nail trauma and a personal or family history of melanoma, Lipner said.
I suppose that doesn't negate any theoretical risks of extra UV exposure to the fingers (not just the nails), but I found it interesting in any case.