Evidence From Humans
 
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Interaction between genetic polymorphism of cytochrome P450-1B1 and environmental pollutants in breast cancer risk
Saintot, M., Malaveille, C., Hautefeuille, A., Gerber, M. European Journal of Cancer Prevention. 2004. 13:1, 83-6.
Topic area
Environmental pollutant - Genetic variability
Study design
Other: Case-series analysis
Funding agency
Other: Association de recherche sur le cancer, Fra
Study Participants
Menopausal Status
The menopausal status of women included in this study is listed here.
Pre menopausal
Post menopausal
Participant selection: Inclusion and exclusion criteria
Criteria used to select participants in the study.
Cases were breast cancer patients admitted to the surgical ward of the Cancer Centre in Montpelier, France, from 1998 to 2001.
Exposures investigated
Length of residence near an incinerator or an agricultural environment. Cytochrome P450 1B1 genotype: leu/leu, val/leu, val/val; used PCR RFLP
How exposure was measured
Biological Questionnaire, in person
Statistical Analysis
Ethnic groups with separate analysis
If this study provided a separate analysis by ethnic or racial group, the groups are listed here.
No
Confounders considered
Other breast cancer risk factors, such as family history, age at first birth, and hormone replacement therapy use, that were taken into account in the study.
Age, menopausal status. BMI, age at menarche, age at first full-term pregnancy, parity, use of oral contraceptives, smoking.
Genetic characterization included
If the study analyzed relationships between environmental factors and inherited genetic variations, this field will be marked “Yes.” “No”, if not.
Yes
Description of major analysis
Case series analysis of relationship between exposure duration and genotype in cases. Logistic regression was used to calculate the interaction odds-ratios.
Strength of associations reported
The odds-ratio for breast cancer among women who are either heterozygous or homozygous for the 'val' allele and who have been in the vicinity of an incinerator for over 10 years is 3.26 (95% CI: 1.2-8.84), compared to women homozygous for the 'leu' allele and who have no exposure to an incinerator.

The odds-ratio for breast cancer among women who are either heterozygous or homozygous for the 'val' allele and who have been exposed to an agricultural environment for over 20 years is 2.18 (95% CI: 1.1-4.32), compared to women homozygous for the 'leu' allele and who have no exposure to an agricultural environment.
Results Comments
The results suggest that the 'leu' allele of the CYP1B1 gene, which has lower catalytic efficiency for hydroxylation of estrogens, may decrease the breast cancer susceptibility of women exposed to environmental pollutants. If the exposure measure (duration of exposure) specified which compounds the women have been exposed to (for example, with a serum or adipose tissue measure), then firmer conclusions could be drawn.
Author address
Groupe d'Epidemiologie Metabolique, Centre de Recherche en Cancerologie, INSERM-CRLC, 34298 Montpellier Cedex 5, France. marietger@valdorel.fnclcc.fr
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