title: CYP1A1 and CYP1B1 polymorphisms and risk of lung cancer among never smokers: a population-based study.
abstract: The cytochrome P450 (CYP) superfamily of enzymes catalyse one of the first steps in the metabolism of carcinogens such as polycyclic aromatic hydrocarbons, nitroaromatics and arylamines. Polymorphisms within the CYP1A1 gene have been shown to be associated with lung cancer risk, predominantly among Asian populations. Despite functional evidence of a possible role of CYP1B1 in lung cancer susceptibility, only a few studies have evaluated polymorphisms in this gene in relation to lung cancer susceptibility. This population-based study evaluates polymorphisms in both of these CYP genes within never smokers, most of whom had environmental tobacco smoke (ETS) exposure. Cases (n = 160) were identified through the metropolitan Detroit Surveillance, Epidemiology and End Results program, and age, sex and race-matched population-based controls (n = 181) were identified using random digit dialing. Neither CYP1A1 MspI nor CYP1A1 Ile(462)Val was associated with lung cancer susceptibility among Caucasians or African-Americans. Among Caucasians, however, CYP1B1 Leu(432)Val was significantly associated with lung cancer susceptibility odds ratio (OR) for at least one valine allele = 2.87 [95% confidence interval (CI) 1.63-5.07]. Combinations of this Phase I enzyme polymorphism along with selected Phase II enzyme polymorphisms (GSTM1 null, GSTP1 Ile(105)Val and NQO1 C(609)T) were evaluated. The combination of CYP1B1 Leu(432)Val and NQO1 C(609)T appeared to be associated with the highest risk of lung cancer (OR = 4.14, 95% CI 1.60-10.74), although no combinations differed significantly from the risk associated with CYP1B1 Leu(432)Val alone. When individuals were stratified by household ETS exposure (yes/no), CYP1B1 Leu(432)Val alone and in combination with Phase II enzyme polymorphisms was more strongly associated with increased lung cancer susceptibility among those with at least some household ETS exposure. Additional studies will be required to further validate these findings among never smokers and to evaluate the effects of this polymorphism among smoking populations as well.
authors.affiliation: Population Studies and Prevention Program, Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA. wenzlaff@med.wayne.edu
authors.forename: A S
authors.initials: AS
authors.lastname: Wenzlaff
authors.forename: M L
authors.initials: ML
authors.lastname: Cote
authors.forename: C H
authors.initials: CH
authors.lastname: Bock
authors.forename: S J
authors.initials: SJ
authors.lastname: Land
authors.forename: S K
authors.initials: SK
authors.lastname: Santer
authors.forename: D R
authors.initials: DR
authors.lastname: Schwartz
authors.forename: A G
authors.initials: AG
authors.lastname: Schwartz
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics; D001741:Black or African American / Q000235:genetics; D000483:Alleles; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D018287:Carcinoma, Large Cell / Q000235:genetics; D018288:Carcinoma, Small Cell / Q000235:genetics; D002294:Carcinoma, Squamous Cell / Q000235:genetics; D016022:Case-Control Studies; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics*; D065633:Cytochrome P-450 CYP1B1; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D051549:Glutathione S-Transferase pi / Q000235:genetics; D005982:Glutathione Transferase / Q000235:genetics; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics; D011110:Polymorphism, Genetic; D012307:Risk Factors; D018426:SEER Program; D012907:Smoking; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014481:United States / Q000453:epidemiology; D044465:White People / Q000235:genetics
chemical_list: D014028:Tobacco Smoke Pollution; D001189:Aryl Hydrocarbon Hydroxylases; C585496:CYP1B1 protein, human; D019363:Cytochrome P-450 CYP1A1; D065633:Cytochrome P-450 CYP1B1; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; C413545:glutathione S-transferase T1; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase