Promoter length polymorphism in UGT1A1 and the risk of sporadic colorectal cancer.

Uridine diphosphoglucuronate glucuronosyltransferase 1A1 (UGT1A1) is the key hepatic detoxification enzyme involved in the biotransformation of many carcinogens implicated in the development of colon, breast, and prostate cancers in humans. A polymorphism in the UGT1A1 promoter containing a TA-repeat element [(TA)5-8TAA] is involved in the modulation of UGT1A1 transcriptional activity. The wild-type activity is associated with the (TA)6TAA allele (UGT1A1*1), whereas UGT1A1 expression decreases with the increase of the TA-repeat number.