Decoding the Molecular Basis for the Population Mechanism of the Triplet Phototoxic Precursors in UVA Light-Activated Pyrimidine Anticancer Drugs

Thiopurines have diverse clinical applications and their long-term use as anti-rejection drugs in transplant patients has been associated with a significantly increased risk of various types of cancer. Although they are slowly being replaced by a new generation of non-thiopurine immunosuppressants, it is anticipated that their use in the management of inflammatory and autoimmune diseases will continue to increase. Therapy-related cancer will remain a potential consequence of prolonged treatment for these generally non-life-threatening conditions. Understanding how thiopurines contribute to the development of cancer will facilitate clinical decisions about the potential risks to patients of long-term treatment for chronic inflammatory disorders.

Research on antimetabolites of nucleic acid purines led to drugs for the treatment of acute leukemia (6-mercaptopurine and thioguanine), gout and hyperuricemia (allopurinol), and herpesvirus infections (acyclovir), and for the prevention of organ transplant rejection (azathioprine).