title: Interindividual variation in CYP1A1 expression in breast tissue and the role of genetic polymorphism.
abstract: The cytochrome P4501A1 (CYP1A1) enzyme is regulated at the transcriptional level and its expression is influenced by genetic factors, polymorphisms in the structural and regulatory genes, and by environmental factors such as exposure to polycyclic aromatic hydrocarbons (PAHs). To investigate the role of CYP1A1 in breast cancer, we studied CYP1A1 expression in breast tissue, thereby taking all possible modifying factors into account. We measured CYP1A1 expression in 58 non-tumor breast tissue specimens from both breast cancer patients (n = 26) and cancer-free individuals (n = 32) using a newly developed reverse transcription-polymerase chain reaction assay. CYP1A1 expression varied between specimens approximately 400-fold and was independent of age. CYP1A1 expression was somewhat higher in tissue from breast cancer patients than in that from cancer-free individuals, but this difference was not statistically significant. Analysis for CYP1A1 genetic polymorphisms revealed eight variants, seven in the cancer-free group and one in the patient group. The variant genotype was not a good predictor of expression level. We conclude that high CYP1A1 expression could be a risk factor for breast cancer and that the known CYP1A1 polymorphisms are not good predictors of CYP1A1 expression.
authors.affiliation: Lawrence Berkeley National Laboratory, Environmental Energy Technology Division, Life Sciences Division and Information and Computing Sciences Division, One Cyclotron Road, Berkeley, CA 94720, USA. r_goth-goldstein@lbl.gov
authors.forename: R
authors.initials: R
authors.lastname: Goth-Goldstein
authors.forename: M R
authors.initials: MR
authors.lastname: Stampfer
authors.forename: C A
authors.initials: CA
authors.lastname: Erdmann
authors.forename: M
authors.initials: M
authors.lastname: Russell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D001940:Breast / Q000201:enzymology* / Q000502:physiology; D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics; D019363:Cytochrome P-450 CYP1A1 / Q000096:biosynthesis / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D006801:Humans; D007206:Individuality; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012307:Risk Factors
chemical_list: D019363:Cytochrome P-450 CYP1A1