Light can also split photocarcinogens, releasing free radicals, whose unpaired electrons cause them to be extremely reactive.
DNA absorption of UV radiation can also lead to TC, CC, and TT lesions but with much less frequency.
[2] In addition, UV radiation often increases the production of cytokines such as interleukin-10 which indirectly hinder antigen presentation in cells.
Oxybenzone (a component of some sunscreens) is suspected owing to its skin penetrating qualities and its production of free radicals.
Epidemiological studies dating back to the 1970s have shown a strong association between psoralen treatment and skin cancer incidence 5 to 15 years afterwards.