HLA-DM polymorphism and risk of trichloroethylene induced medicamentosa-like dermatitis / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To establish the association between genetic polymorphisms of HLA-DMA and HLA-DMB and risk of developing trichloroethylene-induced medicamentosa-like dermatitis (TIMLD).</p><p><b>METHODS</b>Sixty-one cases were medically confirmed to have been affected with TIMLD and 60 controls were selected from exposed workers who were free from TIMLD. The TIMLD cases and controls were similar in terms of age, sex, and duration of exposure. DNA was extracted both from the TIMLD cases and controls, HLA-DMA and HLA-DMB loci were amplified by using Touchdown PCR, and the alleles and genotypes were confirmed by restriction fragment length polymorphism (RFLP) and direct sequencing. Finally, the frequencies of HLA-DMA and HLA-DMB variants were compared between the two groups.</p><p><b>RESULTS</b>The results showed that the frequency of HLA-DMA*0101 and HLA-DMB*0103 alleles was significantly increased in TIMLD patients than in controls (71.3% vs. 55.0% for HLA-DMA*0101; P<0.05) (11.5% vs. 3.3% for HLA-DMB*0103; P<0.05). In addition, the frequency of HLA-DMA*0102-*0102 homozygous genotype was also significantly higher in the controls than in the patients (25.0% vs. 8.2%, P<0.05), whereas the frequency of heterozygous HLA-DMB *0101-*0102 genotype was lower in the patients in comparison with the controls. Conclusion The polymorphisms of HLA-DM may be associated with the susceptibility to TIMLD.</p>

Estimation of gene-environment interaction regarding partial case-control study with missing data on gene information of the controls / 中华流行病学杂志

<p><b>OBJECTIVE</b>To discuss the estimation on gene-environment interaction in partial case-control studies when gene information of the controls was partly missing.</p><p><b>METHODS</b>The results of hot deck multiple imputation and listwise deletion analysis were compared when missing data was generated using Monte Carlo method in Stata 9.0.</p><p><b>RESULTS</b>Coefficients of environment effect, gene effect and gene-environment interaction were respectively estimated by means of hot deck multiple imputation and listwise deletion when approaching to those complete data with missing part less than 50 percent. Both estimated variances of the two methods were increasing with the increased proportion of missing data, but the estimated variance of hot deck multiple imputation was smaller than the one with listwise deletion in each proportion.</p><p><b>CONCLUSION</b>Hot deck imputation could be adopted to make full use of existing information to estimate gene-environment interaction in the partial case-control study when missing proportion of gene data of controls was less than 50 percent so as to increase the precision of the estimation.</p>

The association of polymorphisms of CDT1 and GMNN gene with the risk of breast cancer in Chinese women: a case-control analysis / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the association of polymorphisms of CDT1 and GMNN gene, two important genes participating in DNA replication, with the risk of sporadic breast cancer.</p><p><b>METHODS</b>Using polymerase chain reaction-restriction fragment length polymorphism (PCR - RFLP) and the primer-introduced restriction analysis (PIRA)-PCR assay to genotype the CDT1 838G/A and GMNN 387C/A polymorphisms in a case-control study of 427 breast cancer cases and 477 cancer-free controls in a Chinese population.</p><p><b>RESULTS</b>No significant association of the CDT1 838G/A and GMNN 387C/A polymorphisms with the risk of breast cancer was found (adjusted OR:1.16, 95% CI:0.88-1.54 for CDT1 GA+AA genotypes and adjusted OR:0.90, 95% CI:0.67-1.21 for GMNN CA+AA genotypes). However, in the stratified analyses, a significant association of CDT1 GA+AA genotypes with breast cancer risk among subjects with family history of cancer was found (adjusted OR:2.21, 95% CI:1.20-4.09).</p><p><b>CONCLUSION</b>These findings suggest that the CDT1 838G/A and GMNN 387C/A polymorphisms may not play a major role in the etiology of breast cancer, but CDT1 variant may have a potential role only in genetically susceptible women.</p>

Estimation on gene-environment interaction in the partial case-control study / 中华流行病学杂志

<p><b>OBJECTIVE</b>To introduce the approaches for estimating gene-environment interaction based on partial case-control studies.</p><p><b>METHODS</b>The effects of logistic model and log-linear model for estimating the main effects and gene-environment interaction effect were estimated by means of maximum likelihood methods in traditional case-control studies, case-only studies and partial case-control studies, respectively. An example was also illustrated.</p><p><b>RESULTS</b>In traditional case-control study with complete data, the results of logistic model and log-linear model were equivalent. In case-only study without any information about controls, the logistic model can also efficiently estimate gene-environment interaction. In partial case-control study, environmental information was collected from all of the cases and controls, while genetic information was only collected from cases. For this case-control study with incomplete data, a suitable parameterized log-linear model could simultaneously and efficiently estimate the main effect of environment and gene-environment interaction, whereas the logistic model could not.</p><p><b>CONCLUSION</b>For a partial case-control study, log-linear model could estimate not only the main effect of environment but also gene-environment interaction. If genotype and exposure were independent, estimators from partial case-control were as precisely as those from complete-data case-control studies.</p>