Ke Xin Chen

ABO blood groups and risk of cancer: a systematic review and meta-analysis.

BACKGROUNDnFor decades, studies have been performed to evaluate the association between ABO blood groups and risk of cancer. However, whether ABO blood groups are associated with overall cancer risk remains unclear. We therefore conducted a meta-analysis of observational studies to assess this association.nnnMATERIALS AND METHODSnA search of Pubmed, Embase, ScienceDirect, Wiley, and Web of Knowledge databases (to May 2013) was supplemented by manual searches of bibliographies of key retrieved articles and relevant reviews. We included case-control studies and cohort studies with more than 100 cancer cases.nnnRESULTSnThe search yielded 89 eligible studies that reported 100,554 cases at 30 cancer sites. For overall cancer risk, the pooled OR was 1.12 (95%CI: 1.09-1.16) for A vs. non- A groups, and 0.84 (95%CI: 0.80-0.88) for O vs. non-O groups. For individual cancer sites, blood group A was found to confer increased risk of gastric cancer (OR=1.18; 95%CI: 1.13-1.24), pancreatic cancer (OR=1.23; 95%CI: 1.15-1.32), breast cancer (OR=1.12; 95%CI: 1.01-1.24), ovarian cancer (OR=1.16; 95%CI: 1.04-1.27), and nasopharyngeal cancer (OR=1.17; 95%CI: 1.00-1.33). Blood group O was found to be linked to decreased risk of gastric cancer (OR=0.84; 95%CI: 0.80-0.88), pancreatic cancer (OR=0.75; 95%CI: 0.70-0.80), breast cancer (OR=0.90; 95%CI: 0.85-0.95), colorectal cancer (OR=0.89; 95%CI: 0.81-0.96), ovarian cancer (OR=0.76; 95%CI: 0.53-1.00), esophagus cancer (OR=0.94; 95%CI: 0.89-1.00), and nasopharyngeal cancer (OR=0.81; 95%CI: 0.70-0.91).nnnCONCLUSIONSnBlood group A is associated with increased risk of cancer, and blood group O is associated with decreased risk of cancer.

Association between Dietary Factors and Breast Cancer Risk among Chinese Females: Systematic Review and Meta-analysis

BACKGROUNDnEvidence for associations between dietary factors and breast cancer risk is inconclusive among Chinese females. To evaluate this question, we conducted a systematic review of relevant case-control and cohort studies.nnnMETHODSnStudies were systematically searched among 5 English databases (PudMed, ScienceDirect, Wiley, Clinicaltrials.gov, and Cochrane) and 3 Chinese databases (CNKI, WanFang, and VIP) until November 2012. Random effects models were used to estimate summary odds ratios (ORs) and the corresponding 95% confidence intervals (CIs).nnnRESULTSnThirty one case-control studies and two cohort studies involving 9,299 cases and 11,413 controls were included. Consumption of both soy and fruit was significantly associated with decreased risk of breast cancer, with summary ORs of 0.65 (95% CIs: 0.43-0.99; I2=88.9%, P<0.001; N=13) and 0.66 (95% CIs: 0.47-0.91; I2=76.7%, P<0.001; N=7), respectively. Consumption of fat was significantly associated with increased risk of breast cancer (OR=1.36; 95% CIs: 1.13-1.63; I2=47.9%, P=0.088; N=6). There was non- significant association between consumption of vegetables and breast cancer risk (OR=0.72; 95% CIs: 0.51-1.02; I2= 74.4%, P<0.001; N=9). However, sensitivity analysis based on adjusted ORs showed decreased risk of breast cancer was also associated with consumption of vegetables (OR=0.49; 95% CIs: 0.30-0.67).nnnCONCLUSIONnBoth soy food and fruit are significantly associated with decreased risk of breast cancer among Chinese females, and vegetables also seems to be protective while dietary fatexerts a promoting influence.

Tea Consumption, Alcohol Drinking and Physical Activity Associations with Breast Cancer Risk among Chinese Females: a Systematic Review and Meta-analysis

OBJECTIVEnTo evaluate associations between tea consumption, alcohol drinking and physical activity and breast cancer risk among Chinese females.nnnMETHODSnThree English databases (PubMed, ScienceDirect and Wiley) and three Chinese databases (CNKI, WanFang and VIP) were independently searched by 2 reviewers up to December 2012, complemented by manual searches. The quality of included studies was assessed with the Newcastle-Ottawa Scale items. Random-effects models were used to estimate the pooled odds ratios (ORs) and 95% confidence intervals (CIs). Potential publication bias was estimated through Eggers and Beggs tests. Heterogeneity between studies was evaluated with I2 statistics.nnnRESULTSnThirty-nine studies involving 13,204 breast cancer cases and 87,248 controls were identified. Compared with non-drinkers, regular tea drinkers had decreased risk (OR=0.79, 95%CIs: 0.65-0.95; I2=84.9%; N=16). An inverse association was also found between regular physical activity and breast cancer risk (OR=0.73, 95%CIs: 0.63-0.85; I2=77.3%; N=15). However, there was no significant association between alcohol drinking and breast cancer risk (OR=0.85, 95%CIs: 0.72- 1.02; I2=63.8%; N=26). Most of the results from the subgroup analysis were consistent with the main results.nnnCONCLUSIONnTea consumption and physical activity are significantly associated with a decreased risk of breast cancer in Chinese females. However, alcohol drinking may not be associated with any elevation of risk.

Active and passive smoking with breast cancer risk for Chinese females: a systematic review and meta-analysis.

Previous studies suggested that smoking and passive smoking could increase the risk of breast cancer, but the results were inconsistent, especially for Chinese females. Thus, we systematically searched cohort and case-control studies investigating the associations of active and passive smoking with breast cancer risk among Chinese females in four English databases (PubMed, Embase, ScienceDirect, and Wiley) and three Chinese databases (CNKI, WanFang, and VIP). Fifty-one articles (3 cohort studies and 48 case-control studies) covering 17 provinces of China were finally included in this systematic review. Among Chinese females, there was significant association between passive smoking and this risk of breast cancer [odds ratio (OR): 1.62; 95% confidence interval (CI): 1.39–1.85; I2 = 75.8%, P < 0.001; n = 26] but no significant association between active smoking and the risk of breast cancer (OR: 1.04; 95% CI: 0.89–1.20; I2 = 13.9%, P = 0.248; n = 31). The OR of exposure to husbands smoking and to smoke in the workplace was 1.27 (95% CI: 1.07–1.50) and 1.66 (95% CI: 1.07–2.59), respectively. The OR of light and heavy passive smoking was 1.11 and 1.41, respectively, for women exposed to their husbands smoke (< 20 and ≥ 20 cigarettes per day), and 1.07 and 1.87, respectively, for those exposed to smoke in the workplace (< 300 and ≥ 300 min of exposure per day). These results imply that passive smoking is associated with an increased risk of breast cancer, and the risk seems to increase as the level of passive exposure to smoke increases among Chinese females. Women with passive exposure to smoke in the workplace have a higher risk of breast cancer than those exposed to their husbands smoking.

A bird's eye view of the air pollution-cancer link in China

Air pollution in China comes from multiple sources, including coal consumption, construction and industrial dust, and vehicle exhaust. Coal consumption in particular directly determines the emissions of three major air pollutants: dust, sulfur dioxide (SO2), and nitrogen oxide (NOx). The rapidly increasing number of civilian vehicles is expected to bring NOx emission to a very high level. Contrary to expectations, however, existing data show that the concentrations of major pollutants [particulate matter-10 (PM10), SO2, and nitrogen dioxide (NO2)] in several large Chinese cities have declined during the past decades, though they still exceed the national standards of ambient air quality. Archived data from China does not fully support that the concentrations of pollutants directly depend on local emissions, but this is likely due to inaccurate measurement of pollutants. Analyses on the cancer registry data show that cancer burden related to air pollution is on the rise in China and will likely increase further, but there is a lack of data to accurately predict the cancer burden. Past experience from other countries has sounded alarm of the link between air pollution and cancer. The quantitative association requires dedicated research as well as establishment of needed monitoring infrastructures and cancer registries. The air pollution-cancer link is a serious public health issue that needs urgent investigation.

Association Between the (GT)n Polymorphism of the HO-1 Gene Promoter Region and Cancer Risk: a Meta-analysis

BACKGROUNDnSeveral studies have previously focused on associations between the (GT)n repeat polymorphism of the heme oxygenase-1 (HO-1) gene promoter region and risk of cancers, but results are complex. We conducted the present meta-analysis to integrate relevant findings and evaluate the association between HO-1 (GT)n repeat polymorphism and cancer susceptibility.nnnMATERIALS AND METHODSnPublished literature was retrieved from the PubMed/MEDLINE, EMBASE and ISI Web of Science databases before November 2013. For all alleles and genotypes, odds ratios were pooled to assess the strength of the associations using either fixed-effects or random-effects models according to heterogeneity. Subgroup analysis was conducted according to ethnicity and histopathology.nnnRESULTSnA total of 10 studies involving 2,367 cases and 2,870 controls were identified. The results showed there was no association between HO-1 (GT)n repeat polymorphism and the cancer risk both at the allelic and genotypic level. However, in the stratified analysis, we observed an increased risk of squamous cell carcinoma in persons carrying the LL genotype and the LL+LS genotype as compared with those carrying the SS genotype. When the LS and SS genotypes were combined, the odds ratio for squamous cell carcinoma in LL-genotype carriers, were also significantly increased. No publication bias was observed.nnnCONCLUSIONSnThe LL genotype and L-allele carrying genotypes (LL+LS) of HO-1 (GT)n repeat polymorphism are potential genetic factors for developing squamous cell carcinoma. More large and well-designed studies are required for further validations.

SNP rs16917496 within SETS 3′UTR is associated with the age of onset of breast cancer

OBJECTIVEnWe have identified a SNP within the seed-binding region for miR-502 in the 3-UTR of the SET8 gene that codes for a methyltransferase for histone H4. SET8 methylates TP53 and thus regulates cell proliferation and genome stability. This study is to investigate the role for this SNP and its interaction with the TP53 codon 72 SNP in the age of onset of breast cancer.nnnMETHODSnWe conducted a case-only study of 1, 110 breast cancer cases. PCR-RFLP was used for SNP genotyping. Ages of onset of breast cancer among different genotypes were analyzed using SAS software.nnnRESULTSnOur analysis revealed that the SET8 CC and TP53 GG genotypes were independently associated with earlier age of onset of breast cancer in an allele-dose dependent manner. Moreover, individuals with both SET8 CC and p53 GG genotypes developed cancer at age of 47.74 years, compared with 54.55 years for individuals with both SET8 TT and TP53 CC genotypes.nnnCONCLUSIONSnmiR-502-binding SNP in SET8 may modulate SET8 expression and contribute to early development of breast cancer either independently or together with the TP53 codon 72 SNP.

Pouch size influences clinical outcome of pouch construction after total gastrectomy:A meta-analysis

AIMnTo assess the clinical significance of pouch size in total gastrectomy for gastric malignancies.nnnMETHODSnWe manually searched the English-language literature in PubMed, Cochrane Library, Web of Science and BIOSIS Previews up to October 31, 2013. Only randomized control trials comparing small pouch with large pouch in gastric reconstruction after total gastrectomy were eligible for inclusion. Two reviewers independently carried out the literature search, study selection, data extraction and quality assessment of included publications. Standard mean difference (SMD) or relative risk (RR) and corresponding 95%CI were calculated as summary measures of effects.nnnRESULTSnFive RCTs published between 1996 and 2011 comparing small pouch formation with large pouch formation after total gastrectomy were included. Eating capacity per meal in patients with a small pouch was significantly higher than that in patients with a large pouch (SMD = 0.85, 95%CI: 0.25-1.44, I(2) = 0, P = 0.792), and the operative time spent in the small pouch group was significantly longer than that in the large pouch group [SMD = -3.87, 95%CI: -7.68-(-0.09), I (2) = 95.6%, P = 0]. There were no significant differences in body weight at 3 mo (SMD = 1.45, 95%CI: -4.24-7.15, I(2) = 97.7%, P = 0) or 12 mo (SMD = -1.34, 95%CI: -3.67-0.99, I(2) = 94.2%, P = 0) after gastrectomy, and no significant improvement of post-gastrectomy symptoms (heartburn, RR = 0.39, 95%CI: 0.12-1.29, I(2) = 0, P = 0.386; dysphagia, RR = 0.86, 95%CI: 0.58-1.27, I(2) = 0, P = 0.435; and vomiting, RR = 0.5, 95%CI: 0.15-1.62, I(2) = 0, P = 0.981) between the two groups.nnnCONCLUSIONnSmall pouch can significantly improve the eating capacity per meal after surgery, and may improve the post-gastrectomy symptoms, including heartburn, dysphagia and vomiting.