From: Chapter 15, Ultraviolet Radiation Carcinogenesis
Holland-Frei Cancer Medicine. 5th edition.
Bast RC Jr, Kufe DW, Pollock RE, et al., editors.
Hamilton (ON): BC Decker; 2000.
© 2000, BC Decker Inc.
NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.
![Figure 15.2. Photochemical reactions in a dipyrimidine DNA sequence leading to the formation of CPDs (TpT1, TpT2) or a [6-4]PP (TpT4) and its photolytic derivative, the Dewar pyrimidone (TpT3).](/books/NBK20854/bin/ch15f2.jpg)