Résumé
Objective: To investigate the association of estrogen receptor (ER) codon 325 and progestin receptor (PR) +331G/A gene with the risk of breast cancer and the influence of the two genes combined with the environmental risk factors on breast cancer. Methods: A case-control study was performed. Two hundred and six cases with newly diagnosed breast cancer were collected. Two hundred and fourteen healthy women were matched according to age frequency (± three years). The epidemiological data were collected by questionnaire using structured tables. The 3 mL venous blood was collected and the genotypes of ER codon 325 and PR + 331 G/A were determined by fluorescent quantitative PCR. Results: Compared with CC, the adjusted OR was 0.99 (95% CI: 0.61-1.61) and 1. 13 (95% CI:O. 62-2. 04) for CG genotype and GG genotype of ER-codon 325, respectively. The adjusted OR was 1.51 (95% CI: 0.74-3.07) for GG genotype of PR + 331 G/A. No synergistic effects of ER codon 325 and PR + 331 G/A were observed in increasing the risk of breast cancer (Trend analysis, P = 0.409). The adjusted OR was 3.57 (95% CI: 1. 21-10. 52) for the ER codon 325 CG- and GG-genotyped women with spontaneous abortion history compared with that in CC-genotyped women without spontaneous abortion history. Additive models test demonstrated that the difference tended to be significant (S = 3.06, AP = 0.97, u = 1.898 1 , P = 0.058 8). Conclusion: The single nucleotide polymorphism (SNP) of ER codon 325 and PR + 331 G/A genes are not associated with the risk of breast cancer. The SNP of ER codon 325 with spontaneous abortion history tends to synergistically increase the risk of breat cancer.
Résumé
Objective To study the estrogenic effects of DDT-derivative pesticides. Methods Using a recombinant human estrogen receptor gene yeast cell to estrogenic activity of DDT pesticides. The different concentrations of 17?-estradiol and individual DDT isomers and homologue such as p,p′-DDT, o,p′-DDT, p,p′-DDD and p,p′-DDE and their mixtures were added to yeast cultures, then estrogenic activity was measured by quantification of ?-galactosidase after 4 hours culture. Results DDT showed the ability to play the estrogenic effects like a ligand to bind hER and the dose dependent model existed between the estrogenic effects and the DDT concentration. The relative activity of o,p′-DDT, EC50=5.30?10-7mol/L, was higher and the estrogenic effects of isomers exhibited synergism, AI=1.5. The relative activity of p,p′-DDE , EC50=9.28?10-5mol/L, was lower and the antagonistical action between the homologues was found, AI=-1.38. DDT pesticides presented a synergism, the regression equation was =-2.600 6x2-28.079x-21.757,EC50 was 2.57?10-8mol/L, AI=0.83. Conclusion DDTs are ER mediated environmental estrogens, p,p′-DDT, o,p′-DDT, p,p′-DDD and p,p′-DDE show a synergic effect.