Nucleotide excision repair of carcinogen

Nucleotide excision repair is a DNA repair mechanism. DNA constantly requires repair due to damage that can occur to bases from a vast variety of sources including chemicals but also ultraviolet (UV) light from the sun. Nucleotide excision repair (NER) is a particularly important mechanism by which the cell can prevent unwanted mutations by removing the vast majority of UV-induced DNA damage (mostly in the form of thymine dimers and 6-4-photoproducts). The importance of this repair mechanism is evidenced by the severe human diseases that result from in-born genetic mutations of NER proteins including Xeroderma pigmentosum and Cockayne's syndrome.