• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4403-4407
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• 2012

Background: Glutathione-S-Transferase T1 (GSTT1) gene has been shown to be involved in the development of esophageal cancer. However, the results have been inconsistent. In this study, the authors performed a meta-analysis to clarify the association between GSTT1 polymorphism and esophageal cancer risk among Chinese Han population. Methods: Published literature from PubMed, the China National Knowledge Infrastructure and Wanfang Data were searched. Pooled odds ratio (OR) and 95% confidence interval (95%CI) was calculated using a fixed- or random-effects model. Results: Eleven studies with a total of 2779 individuals were included in the meta-analysis. The results showed that GSTT1 null genotype was significantly associated with esophageal cancer risk in Chinese (OR = 1.31, 95%CI 1.12 to 1.53, p = 0.001). Further sensitivity analyses confirmed the significant association. The cumulative meta-analysis showed a trend of an obvious association between GSTT1 null genotype and esophageal cancer risk as information accumulated by year. Conclusions: This meta-analysis suggests a significant association of GSTT1 null genotype with esophageal cancer risk in the Chinese Han population.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.2009-2011
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• 2015

Objective: Glutathione S-transferase M 1 (GSTM1) is implicated as a risk factor for prostate cancer. However, this issue is not clear in Chinese population. This systemic analysis was conducted to evaluate the effect of GSTM1 null genotypes on prostate cancer risk in Chinese. Methods: Published studies investigating the associations between GSTM1 null genotypes and the risk of prostate cancer in China were identified by using a predefined search strategy. Main statisticals were pooled and estimated according to the primarily reported data. Results: The prevalence of the GSTM1 null genotype was higher in prostate cancer patients than in controls, with significance. Conclusion: The GSTM1 null genotypes is associated with increased risk of prostate cancer in Chinese.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2193-2197
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• 2012

Background: Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme in the metabolism of folate, and the role of MTHFR C677T polymorphism in cervical carcinogenesis is still controversial. Method: We performed a meta-analysis of all relevant case-control studies that examined any association between the C677T polymorphism and cervical cancer risk. We estimated summary odds ratios (ORs) with their confidence intervals (CIs) to assess links. Results: Finally, 10 studies with a total of 2113 cervical cancer cases and 2804 controls were included. Results from this meta-analysis showed that significantly elevated cervical cancer risk was associated with the MTHFR T allele in the Asian population under conditions of two genetic comparison models (for TT vs. CC, OR = 1.37, 95%CI 1.00-1.87, P = 0.050; for TT vs. TC+CC: OR = 1.34, 95%CI 1.01-1.77, P = 0.039). However, there was no obvious association between the MTHFR C677T polymorphism and cervical cancer risk in the other populations. Conclusion: The MTHFR C677T polymorphism is associated with cervical cancer risk in Asians, while any possible link in the Caucasian population needs further studies.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5853-5860
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• 2014

Background: Methylenetetrahydrofolate (MTHFR) is the key enzyme of the folate metabolic pathway and several studies have pointed to association between the MTHFR C677T polymorphism and breast cancer risk. Although significant association was observed in some studies, in others no clear link could be established. Objective: A meta-analysis of published Asian case control studies was therefor carried out to shed further light on any C677T breast cancer association. Materials and Methods: PubMed, Springer Link, Google Scholar and Elsevier databases were searched for case control studies of associations between MTHFR C677T polymorphism and breast cancer risk. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. A total of 36 studies including 8,040 cases and 10,008 controls were included in the present meta-analysis. Results: Overall, a significantly elevated breast cancer risk was associated with the T allele and TT genotype in homozygote comparison and dominant genetic models when all studies were pooled into the meta-analysis (T vs C (allele contrast model): OR=1,23, 95%CI=1.13-1.37, p=0.000 ; TT vs CC(homozygote model): OR=1.38, 95%CI=1.16-1.63, p=0.0003; TT+CT vs CC (dominant model): OR=1.12, 95%CI=1.01-1.23, p=0.02). Conclusions: The present meta-analysis strongly suggested a significant association between the MTHFR C677T polymorphism and risk of breast cancer in Asian populations.

• Journal of Gastric Cancer
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• v.11 no.3
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• pp.135-140
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• 2011

Gastric cancer has been the most commonly diagnosed cancer in Korea although the age-standardized mortality and incidence has decreased gradually during last two decades. $Helicobacter$ $pylori$ infection and cigarette smoking are well-established risk factors, and the role of dietary factors, such as salted foods, fresh vegetables and fruits, soy foods, and processed or grilled meats on gastric carcinogenesis has been suggested. In this review, we review national and international gastric cancer statistics, studies on environmental risk factors conducted in the Korean population, and gastric cancer screening activities.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6743-6749
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• 2013

Molecular epidemiological studies have shown that gene polymorphisms of estrogen receptor alpha gene (ESR-${\alpha}$) are associated with breast cancer risk. However, previous results from many molecular studies have been inconsistent. In this study, we examined two polymorphisms (PvuII and XbaI RFLPs) of the ESR-${\alpha}$ gene in 542 breast cancer cases and 1,016 controls from China. Associations between the polymorphisms and breast cancer risk were calculated with an unconditional logistic regression model. Linkage disequilibrium and haplotypes were analyzed with the SHEsis software. In addition, we also performed a systematic meta-analysis of 24 published studies evaluating the association. No significant associations were found between the PvuII polymorphism and breast cancer risk. However, a significantly decreased risk of breast cancer was observed among carriers of the XbaI 'G' allele (age-adjusted OR = 0.80; 95% CI = 0.66- 0.97) compared with carriers of the 'A' allele. Haplotype analysis showed significantly decreased cancer risk for carriers of the 'CG' haplotype (OR = 0.79; 95% CI = 0.66- 0.96). In the systematic meta-analysis, the XbaI 'G' allele was associated with an overall significantly decreased risk of breast cancer (OR = 0.90, 95% CI = 0.82- 1.00). In addition, the PvuII 'C' allele showed a 0.96- fold decreased disease risk (95% CI = 0.92- 0.99). In subgroup analysis, an association between the PvuII 'C' and XbaI 'G' alleles and breast cancer risk was significant in Asians ('C' vs. 'T': OR = 0.93, 95% CI = 0.85- 1.00; 'G' vs. 'A': OR = 0.82, 95% CI = 0.68- 0.98), but not in Euro-Americans. Thus, our results provide evidence that ESR-${\alpha}$ polymorphisms are associated with susceptibility to breast cancer. These associations may largely depend on population characteristics and geographic location.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2481-2484
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• 2012

Aim: The risk factors mostly strongly associated with gastric cancer are gastric bacteria Helicobacter pylori and diet. Using a case-control study among residents in Jinan, we examined the association between the salt taste and gastric cancer according to H. pylori infection, smoking and histological type as well as tumor site. Methods: This population-based case-control study included 207 cases and 410 controls. Data on potential risk factors of gastric cancer were obtained by interview of cases and controls with a questionnaire, salt taste preference was measured for all subjects, and IgG antibodies to H. pylori were applied to assess infection. Risk measures were determined using unconditional logistic regression. Results: The proportions of salt taste at intervals of 1.8-7.2 g/L and ${\geq}7.2$ g/L were significantly higher in cases than controls, with ORs of 1.56 (1.23-3.64) and 2.03 (2.12-4.11), respectively, subjects with high salt intake having an elevated risk for gastric cancer when infected with H. pylori. Significant modification by smoking and tumor site was observed across the different measures of salt intake, the highest salt taste showed higher cancer risk in ever smokers or with non-cardia cancers. Conclusion: Our study supports the view that high intake of sodium is an important dietary risk factor for gastric cancer, with a synergistic effect found between salt and H.pylori and smoking, dependent on the tumor site.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.2959-2965
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• 2015

The incidence and mortality rates of breast cancer in Northeast Brazil are increasing and little is known about prevailing reproductive factors contributing to this increase. A case-control study was conducted in a public hospital of Campina Grande, state of $Para{\acute{i}}ba$, including 81 women with diagnosed invasive breast cancer and 162 age matched (${\pm}5years$) controls. Binominal logistic regression analysis was applied to estimate odds ratio (OR) and confidence intervals (CI) of risk factors. In this model, age at menarche ${\leq}12$ (OR=2.120; CI: 1.043-4.308; p=0.038), single parity (OR=3.748; CI: 1.459-9.627; p=0.06) and reproductive period >10 years (OR=3.042; CI: 1.421-6.512; p=0.04) were identified as independent variables that significantly increased breast cancer risk of parous women. Compared to parous women who never practised breastfeeding, total breastfeeding time > 24 months decreased the risk of breast cancer (OR=0.258; CI: 0.084-0.787; p=0.017). The results indicated that modifiable reproductive factors contribute to breast cancer risk in women included in the present study. Women's knowledge about factors such as the protective effect of breastfeeding could reduce the risk of breast cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.12
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• pp.6269-6272
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• 2012

We conducted a case-control study to determine the association between several potential SNPs of excision repair cross complementing group 5 (XPG) and gastric cancer susceptibility, and roles of XPG polymorphisms in combination with H.pylori infection in determining risk of gastric cancer. In our study, we collected 337 newly diagnosed gastric cancer cases and 347 health controls. Three SNPs of XPG, rs2296147T>C, rs2094258C>T and rs873601G>A, were genotyped using the Taqman real-time PCR method with a 7900 HT sequence detector system. H. pylori infection was diagnosed by ELISA. By multivariate logistic regression analysis, the rs2296147 CC genotype was associated with a decreased risk of gastric cancer (OR=0.52, 95% CI=0.27-0.97), and rs2094258 TT was associated with elevated risk (OR=2.13, 95% CI=1.22-3.35). Positive H.pylori individuals with rs2094258 TT genotypes demonstrated increased risk of gastric cancer (OR=2.13, 95% CI=1.22-3.35), while rs2296147 CC was associated with lower risk among patients with negative H.pylori (OR=0.45, 95%CI=0.22-0.89). Our findings suggested that XPG polymorphisms might contribute to risk of gastric cancer among Chinese populations, but the effect needs to be further validated by larger sample size studies.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.3937-3942
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• 2012

Background: Many studies have investigated possible association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and ovarian cancer risk, but the impact is still unclear owing to the obvious inconsistencies. This study was performed to quantify the strength of the association with a metaanalysis. Methods: We searched the PubMed, Embase, and CNKI databases for studies relating the association between MTHFR C677T polymorphism and ovarian cancer risk and estimated summary odds ratios (ORs) with confidence intervals (CIs) for assessment. Results: Finally, eight studies with a total of 3,379 ovarian cancer cases and 4,078 controls were included into this meta-analysis. Overall the showed that MTHFR C677T polymorphism was not associated with ovarian cancer risk under all genetic models ($OR_{T\;versus\;C}$ = 1.03, 95%CI 0.90-1.18; $OR_{TT\;versus\;CC}$ = 1.08, 95%CI 0.79-1.47; $OR_{TT\;versus\;TC+CC}$ = 1.05, 95%CI 0.80-1.37; $OR_{TT+TC\;versus\;CC}$ = 1.05, 95%CI 0.86-1.21). Meta-analyses of studies with confirmation of HWE also showed no significant association. Subgroup analyses by ethnicity showed there was no significant association in the Caucasians but MTHFR C677T polymorphic variant T contributed to increased risk of ovarian cancer in East Asians. No evidence of publication bias was observed. Conclusion: Meta-analyses of available data show that MTHFR C677T polymorphism is not associated with ovarian cancer risk in Caucasians, but the MTHFR polymorphic variant T may contribute to increased risk in East Asians.