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 (SO(2)), 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), SO(2), and nitrogen dioxide (NO(2))] 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.

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 husband's 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 husband's 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 husband's smoking.

Association of Lung Cancer Risk With the Presence of Both Lung Nodules and Emphysema in a Lung Cancer Screening Trial.

Background: The coexistence of emphysema and lung nodules could interact with each other and then lead to potential higher lung cancer risk. The study aimed to explore the association between emphysema combined with lung nodules and lung cancer risk. Methods: A total of 21,949 participants from the National Lung Screening Trial (NLST) who underwent low-dose computed tomography (LDCT) examination were included. Participants were categorized into four groups (NENN group (non-emphysema and non-nodules), E group (emphysema without nodules), N group (nodules without emphysema), and E + N group (nodules with emphysema)) according to whether there were lung nodules and emphysema. Multivariable Cox regression and stratified analyses were performed to estimate the association between the four groups and lung cancer risk. Results: Among the 21,949 participants, there were 9,040 (41.2%), 5,819 (26.5%), 4,737 (21.6%), and 2,353 (10.7%) participants in the NENN group, E group, N group, and E + N group. The risk of lung cancer incidence increased in turn in NENN group, E group, N group and E + N group. Compared with NENN group, the age-adjusted hazard ratios (HRs) (95% confidence intervals (CIs)) of lung cancer incidence were 2.07 (1.69 - 2.54) for E group, 4.13 (3.47 - 5.05) for N group, and 6.26 (5.14 - 7.62) for E + N group. The association was robust to adjustment for potential confounders (1.83 (1.47 - 2.27) for E group, 3.97 (3.24 - 4.86) for N group, and 5.23 (4.28 - 6.48) for E + N group). Comparable results as the lung cancer incidence were observed for lung cancer mortality, whether in age-adjusted model (E group: 1.85 (1.39 - 2.46), N group: 2.49 (1.89 - 3.29), E + N group: 4.27 (3.21 - 5.68)) or fully adjusted model (E group: 1.56 (1.15 - 2.11), N group: 2.43 (1.81 - 3.26), E + N group: 3.39 (2.50 - 4.61)). However, the trend of all-cause mortality risk among the four groups was somewhat different from that of lung cancer risk, whether in age-adjusted model (1.37 (1.21 - 1.54) for E group, 1.06 (0.92 - 1.21) for N group, and 1.75 (1.51 - 2.02) for E + N group) or fully adjusted model (1.26 (1.10 - 1.44) for E group, 1.09 (0.94 - 1.27) for N group, and 1.52 (1.30 - 1.79) for E + N group). Conclusion: Based on a large-scale lung cancer screening trial in the United States, this study demonstrated that either emphysema or lung nodules can increase lung cancer risk, and lung nodules combined with emphysema can further increase the lung cancer risk and all-cause mortality. The significance of these findings for lung cancer screening should be evaluated.

[SNP rs16917496 within SET8 3'UTR is associated with the age of onset of breast cancer].

OBJECTIVE: We 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. METHODS: We 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. RESULTS: Our 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. CONCLUSIONS: miR-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.

A new risk stratification strategy for fatty liver disease by incorporating MAFLD and fibrosis score in a large US population.

BACKGROUND: Metabolic dysfunction-associated fatty liver disease (MAFLD) is a newly proposed definition of fatty liver disease (FLD) independent of excessive alcohol consumption (EAC) and hepatitis viral infection. Evidence on the mortality risk in different types of FLD [nonalcoholic FLD (NAFLD), alcoholic FLD (AFLD), and MAFLD] is sparse, hindering the identification of high-risk populations for preferential clinical surveillance. METHODS: A total of 11,000 participants in the Third National Health and Nutrition Examination Survey were enrolled. Participants were categorized into three groups [FLD( - ), MAFLD( - ), and MAFLD( +)] according to FLD and MAFLD criteria, and further categorized into six groups by EAC. Multivariate Cox proportional hazard model was used to estimate the risk of all-cause, cardiovascular-related, and cancer-related mortality. RESULTS: During a median follow-up of 23.2 years, a total of 3240 deaths were identified. Compared with FLD( - )/EAC( - ) participants, MAFLD( +) individuals had higher all-cause mortality risk [hazard ratio (HR) = 1.28, 95% confidence interval (CI) = 1.18-1.39] regardless of EAC status [MAFLD( +)/NAFLD: HR = 1.22, 95%CI = 1.11-1.34; MAFLD( +)/AFLD: HR = 1.83, 95%CI = 1.46-2.28], while not for MAFLD( - ) individuals. Furthermore, diabetes-driven-MAFLD had higher mortality risk (HR = 2.00, 95%CI = 1.77-2.27) followed by metabolic dysregulation-driven-MAFLD (HR = 1.30, 95%CI = 1.06-1.60) and overweight/obesity-driven-MAFLD (HR = 1.11, 95%CI = 1.00-1.22). Additionally, MAFLD( - ) participants with elevated fibrosis score were also associated with statistically significantly higher mortality risk (HR = 3.23, 95%CI = 1.63-6.40). CONCLUSIONS: Utilizing a representative sample of the US population, we proved the validity of MAFLD subtype and fibrosis score, rather than the traditional definition (NAFLD and AFLD), in the risk stratification of FLD patients. These findings may be applied to guide the determination of surveillance options for FLD patients.

Single-nucleotide polymorphisms among microRNA: big effects on cancer.

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the transcriptional or posttranscriptional level. Many miRNAs are found to play a significant role in cancer development either as tumor suppressor genes or as oncogenes. Examination of tumor-specific miRNA expression profiles in diverse cancers has revealed widespread deregulation of these molecules, whose loss and overexpression respectively have diagnostic and prognostic significance. Genetic variations, mostly single-nucleotide polymorphisms (SNPs) within miRNA sequences or their target sites, have been found to be associated with many kinds of cancers. In this review, we summarize the current knowledge of miRNAs including their biogenesis and role in cancer development, and finally, how SNPs among miRNAs affect miRNA biogenesis and contribute to cancer.

[Trend analysis of the incidence of prostate cancer in Tianjin between 1981 and 2004].

OBJECTIVE: To analyze the trend of the incidence of prostate cancer in urban Tianjin area between 1981 and 2004 so as to provide scientific rationales for the prevention and control of prostate cancer. METHODS: The data of prostate cancer cases were provided by the Tianjin Cancer Registry. The SAS system V9 was used to calculate the crude incidence, age-adjusted incidence and age specific incidence of prostate cancer in Tianjin between 1981 and 2004. And the Join point 3.0 software was used to analyze secular trends. RESULTS: Between 1981 and 2004, a total of 1060 prostate cancer cases were diagnosed in Tianjin. And the age-adjusted incidence rate was 2.84/100 000 in 2004. The incidence of prostate cancer showed 3 incremental stages during the 24-year period at an annual average of 4.02%. An aging trend was observed for prostate cancer patients. The elder patients had a faster increment in incidence. Specifically, it increased annually at 4.63% for age group 65 - 74 year versus 5.18% for age group 75 years or more. CONCLUSION: Despite a low incidence of prostate cancer in Tianjin, it is increasing at a fast rate. The prevention and control of prostate cancer should be strengthened.

[Epidemiological trend of gastric cancer in Tianjin, 1981-2002].

OBJECTIVE: To explore the secular trend in incidence and mortality rate of gastric cancer in Tianjin and to provide evidence and reference for making prevention and control strategy for gastric cancer. METHODS: Data derived from Tianjin cancer registry system were analyzed by descriptive epidemiological method and Joinpoint model. A total of 17990 gastric cancer cases reported in Tianjin from 1981 to 2002, including 12755 males and 5235 females were studied. RESULTS: The annual percent change (APC) of crude incidence rate for males and females was -0.92% (Z = -3.85, P = 0.001) and -0.79% (Z = -2.67, P = 0.015), while the APC of standard incidence rate was -3.55% (Z = -13.52, P = 0.000) and -3.47% (Z = -12.85, P = 0.000). There was a descending trend of incidence rate in males and females above 45-years-old, however, in male under 45 years it showed an increased trend and in females it kept stable. The APC of crude mortality rate was -1.66% ( Z = -5.79, P = 0.000) for males and -1.84% (Z = -6.02,P = 0.000) for females, while the APC of standard mortality rate was -4.60% ( Z = -15.79, P = 0.000) for females and -5.36% ( Z = -8.28, P = 0.000) for males during 1989-2002. Mortality and incidence ratio also indicated a downward trend. CONCLUSION: Despite its declining trend in Tianjin, gastric cancer still remains an important public health problem in facing of the aging society and many risk factors.

Long-term exposure to urban air pollution and lung cancer mortality: A 12-year cohort study in Northern China.

Cohort evidence that links long-term exposures to air pollution and mortality comes largely from the United States and European countries. We investigated the relationship between long-term exposures to particulate matter <10µm in diameter (PM10), nitrogen dioxide (NO2), and sulfur dioxide (SO2) and mortality of lung cancer in Northern China. A cohort of 39,054 participants were followed during 1998-2009. Annual average concentrations for PM10, NO2, and SO2 were determined based on data collected from central monitoring stations. Lung cancer deaths (n=140) were obtained from death certificates, and hazard ratios (HRs) were estimated using Cox proportional hazards models, adjusting for age, gender, BMI, education, marital status, smoking status, passive smoking, occupation, alcohol consumption, etc. Each 10mg/m(3) increase in PM10 concentrations was associated with a 3.4%-6.0% increase in lung cancer mortality in the time-varying exposure model and a 4.0%-13.6% increase in the baseline exposure model. In multi-pollutant models, the magnitude of associations was attenuated, most strongly for PM10. The association was different in men and women, also varying across age categories and different smoking status. Substantial differences exist in the risk estimates for participants based on assignment method for air pollution exposure.

An analysis: colon cancer mortality in Tianjin, China, from 1981 to 2000.

AIM: To analyze the data from Tianjin Cancer Registry of mortality due to colon cancer from 1981 to 2000 in Tianjin, China. METHODS: Tumors diagnosed in this study were coded according to ICD-9. Mortality rates were calculated by sex and calendar year of diagnosis. RESULTS: Seventy point four percent of colon cancer deaths occurred in the age group of 55-79 years and the mortality rate reached its peak in the age group of 75-80 years. The average age at death was 64.10 years. An ascending trend was observed in the mean age of death due to colon cancer from 1981 through 2000. However, as for the sex ratio, there was no clear trend exhibited. During 1981-2000, the total number of deaths was 2147, 1041 males and 1106 females. The mean mortality rate of colon cancer was 3.04/100,000. The mortality caused by colon cancer ascended from 1981 to 2000. CONCLUSION: The epidemic trend of colon cancer in Tianjin and its risk factors and prevention should be studied further.

Association between the (GT)n polymorphism of the HO-1 gene promoter region and cancer risk: a meta-analysis.

BACKGROUND: Several 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. MATERIALS AND METHODS: Published 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. RESULTS: A 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. CONCLUSIONS: The 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.

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

BACKGROUND: For 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. MATERIALS AND METHODS: A 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. RESULTS: The 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). CONCLUSIONS: Blood group A is associated with increased risk of cancer, and blood group O is associated with decreased risk of cancer.

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

AIM: To assess the clinical significance of pouch size in total gastrectomy for gastric malignancies. METHODS: We 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. RESULTS: Five 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. CONCLUSION: Small pouch can significantly improve the eating capacity per meal after surgery, and may improve the post-gastrectomy symptoms, including heartburn, dysphagia and vomiting.

Association between dietary factors and breast cancer risk among Chinese females: systematic review and meta-analysis.

BACKGROUND: Evidence 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. METHODS: Studies 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). RESULTS: Thirty 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). CONCLUSION: Both 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.

Advances in circulating microRNAs as diagnostic and prognostic markers for ovarian cancer.

Ovarian cancer is one of the most lethal malignant gynecological tumors. More than 70% of patients with ovarian cancer are diagnosed at advanced stage. The 5-year survival in patients with advanced ovarian cancer is less than 30% because of the lack of effective biomarkers for diagnosis, prognosis, and personalized treatment. MicroRNA (miR) is a class of small noncoding RNAs that negatively regulate gene expression primarily through post-transcriptional repression. Many studies on tissue miR in ovarian cancer have been carried out and show great potential in clinical practice. However, tissue samples are not easily available because sampling causes injury. Researchers have started to focus on plasma/serum miR, assuming that blood samples may replace tissue samples in miR research in the future. Plasma/serum miR research is still in its early stages. Studies on its function in the early diagnosis of ovarian cancer have achieved some progress, but plasma/serum miR profiling for prognosis and personalized treatment of ovarian cancer remains unknown. A thorough understanding of the function of plasma/serum miR in ovarian cancer will facilitate early diagnosis and improve treatment for ovarian cancer.

Tea consumption, alcohol drinking and physical activity associations with breast cancer risk among Chinese females: a systematic review and meta-analysis.

OBJECTIVE: To evaluate associations between tea consumption, alcohol drinking and physical activity and breast cancer risk among Chinese females. METHODS: Three 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 Egger's and Begg's tests. Heterogeneity between studies was evaluated with I2 statistics. RESULTS: Thirty-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. CONCLUSION: Tea 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.