The majority of skin cancers are not lethal. Ultraviolet radiation is a well-known mutagen. A mutation can take many years to show up as a symptom. Most skin cancers are found in people over 40 years old, but the actual damage that caused the cancer occurred when these people were children. In the intervening decades, the altered DNA has remained, and the misprint in the gene has been copied into more and more cells.
Sunlight also causes other damage Sunlight doesn t just cause cancer.
It can also cause painful sunburn, which usually shows up the day after exposure. Sunlight also ages skin. Sun-weathered skin becomes leathery and loses its softness and lustre. Other blemishes, such as moles and solar keratoses , can also form. These are unsightly but they are not usually considered dangerous.