Association of polymorphisms in the cyclin D1 and XPD genes and susceptibility to cancers of the upper aero-digestive tract.

DNA repair enzyme genetic polymorphisms have been postulated to increase the risk of certain cancers in the presence of tobacco carcinogen exposures. The XPD protein is an important component of the TFIIH transcription factor complex. XPD genetic polymorphisms resulting in amino acids substitutions may lead to alterations in TFIIH helicase activity, resulting in repair and transcription defects.