[Study on serum organochlorines pesticides (DDTs) level, CYP1A1 genetic polymorphism and risk of breast cancer: a case control study].
OBJECTIVE
To study the potential effect of gene-environment interaction between CYP1A1 and serum dichlorodiphenyldichloroethane (DDT) levels on the risk of breast cancer in women, in China.


METHODS
A case-control study was conducted. From Dec. 2003 to Sep. 2004, 104 women with histologically confirmed breast cancers and 154 noncancerous controls from a community were enrolled in this study. Risk factors information of breast cancer was investigated by a questionnaire. Serum p, p'-dichlorodiphenyldichloroethane (p, p'-DDT) and 1, 1-dichloro-2, 2-bis (p-chlorophenyl) ethylene (p, p'-DDE) levels were tested by GC-ECD. CYP1A1 m2 gene type was tested by allele special-PCR method.


RESULTS
Serum DDT levels of case and control were (36.90 +/- 79.41) ng/ml and (50.60 +/- 150.70) ng/ml respectively. Serum 1, 1-dichloro-2, 2-bis (p-chlorophenyl) ethylene (p, p'-DDE) levels of case and control were (7.43 +/- 11.10) ng/ml and (8.96 +/- 11.30) ng/ml respectively. No statistically significant differences were found between the two groups with geometric mean t-test (P > 0.05). Compared with women who had homozygous wild-type CYP1A1 m2 genotype, significantly increased risks of breast cancer were found for women with the CYP1A1 m2 homozygous variant genotype [odds ratio (OR) = 2.61, 95% confidence interval (CI): 1.00 - 6.80]. Among premenopausal women, compared with women with homozygous wild-type of CYP1A1 genotype (Ile/Ile) and low serum DDT level (DDT serum level < or = 42.93 ng/ml), women with at least one variant allele of CYP1A1 m2 genotype and high serum DDT level (DDT serum level > or = 42.93 ng/ml) had higher risk of breast cancer (OR = 4.35, 95% CI: 1.140 - 16.950).


CONCLUSIONS
CYP1A1 m2 genetic polymorphism was associated with increased risk of female breast cancer while DDT exposure might have increased the risk of breast cancer among premenopausal women with CYP1A1 m2 variant genotype.
Li
Jia-yuan
JY
Huaxi School of Public Health, Sichuan University, Chengdu 610041, China.
Wu
De-sheng
DS
Yang
Fei
F
Zeng
Hong-yan
HY
Lei
Fang-ming
FM
Zhou
Wei-dong
WD
Li
Hui
H
Tao
Ping
P
D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics*; D003633:Dichlorodiphenyl Dichloroethylene / Q000097:blood*; D003632:Dichlorodiphenyldichloroethane / Q000097:blood*; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D005838:Genotype; D006720:Homozygote; D006801:Humans; D007306:Insecticides / Q000097:blood*; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D017697:Premenopause; D012307:Risk Factors
D007306:Insecticides; D003633:Dichlorodiphenyl Dichloroethylene; D019363:Cytochrome P-450 CYP1A1; D003632:Dichlorodiphenyldichloroethane