Relationship between estrogen-biosynthesis gene (CYP17, CYP19, HSD17beta1) polymorphisms and breast cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the relationship between the polymorphism of estrogen-biosynthesis genes (CYP17, CYP19, HSD17beta1) and risk of breast cancer.</p><p><b>METHODS</b>A matched case-control study was designed. From May 2007 to July 2008, 200 pairs of subjects with and without breast cancer were enrolled, who were matched by age and menstruation status. Demographical characteristics, dietary factors and reproductive factors were investigated by questionnaire. CYP17 locus 1931 (T-->C), CYP19 codon 264 (Arg-->Cys) and HSD17beta1 locus 1954 (A-->G) were identified by AS-PCR (allele-specific PCR). The gene-gene interaction were analyzed with the MDR model (multifactor dimensionality reduction). Based on the results of MDR model, an unconditional logistic regression model was simulated to estimate the ORs of interaction factors and other risk factors.</p><p><b>RESULTS</b>The main effect of CYP17, CYP19 and HSD17beta1 susceptible genotypes were not correlated to breast cancer (OR approximately 1, P > 0.05). The positive interaction effect between CYP17 (T 1931C) and HSD17beta1 (A1954G) was discovered by MDR model with a statistically significant difference (Sign test, P = 0.05). The model's testing balance accuracy was 56.00%, and crossing validation consistency was 10/10. Multivariable unconditional logistic regression showed that after adjusting BMI, intake of estrogen, age of first birth, number of abortion and period of breast feeding, the interaction item of CYP17 (T1931C) and HSD17beta1 (A1954G) was strongly and positively correlated to breast cancer (OR = 2.52, 95%CI = 1.54 to 4.11).</p><p><b>CONCLUSION</b>The estrogen-biosynthesis genes CYP17 (T1931C) and HSD17beta1 (A1954G) polymorphism may jointly increase the risk of breast cancer.</p>

Study on the relationship between organochlorine pesticides and level of residues in serum and daily foodstuff / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the contents of organochlorine pesticides in human bodies and residues in serum of populations with non-occupational exposure as well as to study the relationship between organochlorine pesticides in foodstuff and residues levels in serum.</p><p><b>METHODS</b>A cross-section study was conducted. 107 men and 142 women who were all healthy and living in the communities were investigated from Mar. 2004 to Jul. 2004. Level of daily food exposure was estimated through questionnaires while DDTs and HCHs serum levels were detected by EC-ECD. The relationship between organochlorine pesticides contents in foods and residues in serum were analyzed by ridge regression.</p><p><b>RESULTS</b>Fresh fish was positively correlated to men's serum level of beta-HCH and p,p'-DDT (beta = 0.1266 and beta = 0.0595) while vegetables and fruits were negatively correlated to women's serum level of beta-HCH (beta = -0.1066). Soybean was negatively correlated to women's serum level of p,p'-DDE and p,p'-DDT (beta = -0.0965 and 3 = -0.0581). Alcohol consumption was negatively correlated to men's serum level of beta-HCH and p,p'-DDE and women's serum level of p,p'-DDE (beta = -0.1315, beta = -0.1599 and P = -0.1128).Salted meat was negatively correlated to men's serum level of beta-HCH and p, p'-DDT (P = -0. 066 and P = - 0.0569).</p><p><b>CONCLUSION</b>In this study, fresh fish might increase the body burden of organochlorine pesticides and residues while alcohol might promote the excretion of organochlorine pesticides. Pickled meat and vegetal foodstuff might contain low-level of organochlorine pesticides and residues.</p>

Study on serum organochlorines pesticides (DDTs) level, CYP1A1 genetic polymorphism and risk of breast cancer: a case control study / 中华流行病学杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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).</p><p><b>CONCLUSIONS</b>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.</p>