Psoralens (fucocoumarins) are plant-derived chemicals that, in the presence of UV light, create DNA interstrand crosslinks (ICLs) along with other types of DNA lesions. PUVA is a combination therapy consisting of psoralens and UV light, used to treat skin conditions such as psoriasis and severe atopic dermatitis (eczema), as well as the cutaneous T-cell lymphoma (mycosis fungoides). The following psoralens have been widely used in the PUVA therapy:
8-methoxypsoralen (Cohen et al. 1981; Gruenert et al. 1985)
5-methoxypsoralen (Gruenert et al. 1985)
trimethylpsoralen (also known as trioxalen) (Carter et al. 1979).
The PUVA therapy increases the risk of different types of skin cancer, such as basal carcinoma, squamous cell carcinoma, and melanoma. For review, please refer to Deans and West 2011.