Notes: Dihydrothymine is a metabolite of the pyrimidine nucleobase thymine.{66317} It is formed from thymine by dihydropyrimidine dehydrogenase (DPD). Dihydrothymine can also be produced from thymine by UV radiation.{66318} Levels of dihydrothymine are elevated during the epithelial-to-mesenchymal transition (EMT) in human mammary epithelial cells expressing Twist.{66319}