Etiological study of esophageal squamous cell carcinoma in an endemic region: a population-based case control study in Huaian, China. BMC Cancer. 2006;6:287. [PMID: 17173682 DOI: 10.1186/1471-2407-6-287]

Overview of Risk Factors for Esophageal Squamous Cell Carcinoma in China

(1) Background: China has the highest esophageal squamous cell carcinoma (ESCC) incidence areas in the world, with some areas of incidence over 100 per 100,000. Despite extensive public health efforts, its etiology is still poorly understood. This study aims to review and summarize past research into potential etiologic factors for ESCC in China. (2) Methods: Relevant observational and intervention studies were systematically extracted from four databases using key terms, reviewed using Rayyan software, and summarized into Excel tables. (3) Results: Among the 207 studies included in this review, 129 studies were focused on genetic etiologic factors, followed by 22 studies focused on dietary-related factors, 19 studies focused on HPV-related factors, and 37 studies focused on other factors. (4) Conclusions: ESCC in China involves a variety of factors including genetic variations, gene-environment interactions, dietary factors like alcohol, tobacco use, pickled vegetables, and salted meat, dietary behavior such as hot food/drink consumption, infections like HPV, poor oral health, gastric atrophy, and socioeconomic factors. Public health measures should prioritize genetic screening for relevant polymorphisms, conduct comprehensive investigations into environmental, dietary, and HPV influences, enhance oral health education, and consider socioeconomic factors overall as integral strategies to reduce ESCC in high-risk areas of China.

Tea Polyphenols and Their Preventive Measures against Cancer: Current Trends and Directions

Cancer is exerting an immense strain on the population and health systems all over the world. Green tea because of its higher simple catechin content (up to 30% on dry weight basis) is greatly popular as an anti-cancer agent which is found to reduce the risks of cancer as well as a range of other diseases. In addition, several in vitro and in vivo studies have shown that green tea possesses copious health benefits like anti-diabetic, anti-obese, anti-inflammatory, neuro-protective, cardio-protective, etc. This review highlights the anti-carcinogenic effects of green tea catechins integrating the recent information to gain a clear concept. Special emphasis was given to the effectiveness of green tea polyphenols (GTP) in the prevention of cancer. Overall, green tea has been found to be effective to reduce the risks of breast cancer, ovarian cancer, liver cancer, colorectal cancer, skin cancer, prostate cancer, oral cancer, etc. However, sufficient information was not found to support that green tea consumption reduces the risk of lung cancer, esophageal cancer, or stomach cancer. The exciting data integrated into this article will increase interest in future researchers to garner more fruitful information on the relevant topics.

Hot Tea Consumption and Esophageal Cancer Risk: A Meta-Analysis of Observational Studies

Objective

Many laboratory studies have shown that tea consumption protected against the development of esophageal cancer (EC). However, in epidemiological studies, inconsistent or even contradictory results were frequently observed, especially when drinking tea at higher temperatures.

Methods

We conducted a meta-analysis based on published observational studies to explore whether hot tea consumption was a risk factor of EC. Relevant studies were searched in PubMed, Embase, and Web of science up to October 13, 2021, and we also manually retrieved the literature in the included studies and recent reviews.

Results

A total of 23 eligible reports were identified, including 5,050 cases and 10,609 controls, and a meta-analysis with Comprehensive Meta-Analysis (CMA) software (version 2.0) was conducted. A statistically significant increased EC risk was observed when drinking tea at higher temperature (odds ratios (ORs) = 1.79, 95% CI: 1.48–2.15, p = 0.00). Except for esophageal adenocarcinoma (EAC), this increased risk was also found in the majority of subgroups, which are the European and Australian populations.

Conclusions

This meta-analysis showed that people who drank hot tea had a significantly increased risk of Esophageal squamous cell carcinoma (ESCC), but no significant association for EAC.

Trends in Incidence and Mortality of Esophageal Cancer in Huai'an District, a High-Risk Area in Northern Jiangsu Province, China

Purpose

This study aimed to provide a clear comparable figure of the trends in incidence and mortality rates of esophageal cancer (EC) in Huai’an District, Huai’an City, Jiangsu Province, China, a high-risk area for EC.

Methods

The data for age- and sex-specific incidence rates between 1998 and 2016, the mortality rates in 1990-2016 and the number of EC patients were obtained from Huai’an District Cancer Registry. Crude rates, Age-standardized rates (ASRs) by world standard population and truncated age-standardized rates of EC incidence and mortality were calculated. The joinpoint regression analysis was used to calculate the annual percent changes (APC), average annual percent changes (AAPC), and their 95% confidence intervals (CIs).

Results

Overall, 20,892 new EC cases and 20,806 EC deaths were registered in Huai’an District. ASR of EC incidence from 1998 to 2016 and mortality from 1990 to 2016 were 73.32/100,000 and 60.03/100,000, respectively. The ASR illustrated that the incidence of EC had significant downward trends in total, male and female (AAPC = −4.65, −4.90, and −5.51, respectively, p <.01). The age-specific incidence and mortality rates of EC increased dramatically in people over the age of 40, and peaked in people between the ages 70-74. In the subdivisions of Huai’an District, geographical diversities in the crude incidence and mortality rates of EC were found.

Conclusion

In summary, the incidence and mortality rates of EC showed downward trends in Huai’an District. However, the burden of EC still remained serious in this high-risk area. Cost-effective methods of intervention and health education should be enhanced for improving EC prevention.

Precision screening for esophageal squamous cell carcinoma in China

Esophageal squamous cell carcinoma (ESCC) is the predominant subtype of esophageal cancer in China, and this neoplasm is associated with high morbidity and mortality as well as clear geographical heterogeneity. Since primary prevention for ESCC lacks a clear intervention target, secondary prevention, also known as screening and early diagnosis and early treatment, has become the mainstay of ESCC prevention and control in China. ESCC screening in China has been subject to decades of evaluation and practice. However, the ESCC screening strategy currently adopted in China has encountered a developmental bottleneck. In this review, we have summarized studies and significant findings for ESCC screening and proposed advancement of screening strategies as follows: 1) evidence from randomized controlled trials is needed to support the effectiveness and health economic value of endoscopic screening for ESCC; 2) the current traditional screening and surveillance strategies warrant reform, and a risk-prediction-based precision strategy should be established; and 3) a deeper understanding of the value of opportunistic screening in the prevention and control of ESCC in China is called for. Due to the low absolute prevalence of precancerous lesions, substantial investment of resources and nonnegligible risks of invasive screening techniques, precision and individualization should be the main direction of cancer screening programs for the future. We advocate cooperation on the part of Chinese scientists to solve this major China-specific health problem in the next decades.

Urinary exposure of N-nitrosamines and associated risk of esophageal cancer in a high incidence area in China

Esophageal cancer (EC) is a deadly malignancy worldwide with a high incidence and exhibits unevenly geographic prevalence, which suggests that environmental factors are deeply involved in the development of EC. Although the carcinogenesis of nitrosamines in the esophagus has been identified by tremendous toxicological data, the role of nitrosamines in the genesis of human EC has so far proved inconclusive largely due to a lack of convincing evidences. In this study, urinary nitrosamines in population controls and cases with esophageal precancerous lesions, including reflux esophagitis (RE) accompanying with basal cell hyperplasia (BCH) and dysplasia (DYS), and esophageal squamous cell carcinoma (ESCC) were detected by a SPE-LC-MS/MS method and the associated risk was evaluated. Higher excretion concentrations of N-nitrosomethylethylamine (NMEA) in the RE/BCH patients, NMEA and N-nitrosodibutylamine (NDBA) in the DYS patients, and NMEA, NDBA, N-nitrosopyrrolidine (NPyr) and N-nitrosomorpholine (NMor) in the ESCC patients were observed compared with the controls (p < .05). And with the progression of esophageal lesion, the exposure complexity increased in terms of the categories of nitrosamines. Furthermore, the observed positive associations between the hazardous exposure of NMEA, NDBA and NPyr and the increased risk of ESCC, and between NMEA and NDBA and RE/BCH were established. These findings provided direct evidence to support the hypothesis that exposure to nitrosamines are involved in the carcinogenesis of esophageal epithelia in this high incidence area from the perspective of endogenous exposure assessment. However, discoveries in this study need to be confirmed by systematic researches in the future. And the dose-response relationships, the reference ranges or cutoff values to predict the risks of nitrosamines exposure also need to be defined.

Moderately high folate level may offset the effects of aberrant DNA methylation of P16 and P53 genes in esophageal squamous cell carcinoma and precancerous lesions

BACKGROUND

This study evaluated gene-nutrition interactions between folate and the aberrant DNA methylation of tumor suppressor genes in different stages of carcinogenesis of esophageal squamous cell carcinoma (ESCC).

METHODS

Two hundred ESCC cases, 200 esophageal precancerous lesion (EPL) cases, and 200 controls matched by age (± 2 years) and gender were used for this study. Baseline data and dietary intake information was collected via questionnaire. The serum folate levels and methylation status of promoter regions of p16 and p53 were detected.

RESULTS

The interactions of increased serum folate level with unmethylated p16 and p53 promoter regions were significantly associated with a reduced risk of both EPL and ESCC (p for interaction < 0.05). The interactions of the lowest quartile of serum folate level with p16 or p53 methylation was significantly associated with an increased risk of ESCC (OR = 2.96, 95% CI, 1.45-6.05; OR = 2.34, 95% CI, 1.15-4.75). An increased serum folate level was also related to a decreasing trend of EPL and ESCC risks when p16 or p53 methylation occurred. The interaction of spinach, Chinese cabbage, liver and bean intake with unmethylated p16 and p53 was significantly associated with a reduced risk of EPL or ESCC (p for interaction < 0.05).

CONCLUSIONS

The interactions between a high folate level and unmethylated p16 and p53 promoter regions may have a strong preventive effect on esophageal carcinogenesis. Additionally, a high folate level may offset the tumor-promoting effects of aberrant DNA methylation of the genes, but it is also noteworthy that a very high level of folate may not have a protective effect on EPL in some cases.

Corn Flour Intake, Aflatoxin B1 Exposure, and Risk of Esophageal Precancerous Lesions in a High-Risk Area of Huai'an, China: A Case-Control Study

Aflatoxin B₁ (AFB₁), which has potent toxicity and carcinogenicity, is a common contaminant of important agricultural commodities. This study aimed to investigate the frequency of corn flour intake and assess the exposure to AFB₁ via direct detection of AFB₁ in the diet and serum AFB₁ exposure biomarker, so as to evaluate their associations with the risk of esophageal precancerous lesions (EPL). A case-control study based on three-day duplicate diet samples was performed in Huai'an District. One hundred EPL cases and 100 healthy controls were enrolled and required to be age- (±2 years) and gender-matched. The concentration of AFB₁ in food samples and the level of serum AFB₁-albumin (AFB₁-Alb) adduct were quantitatively analyzed. Results showed that corn flour intake was positively associated with serum AFB₁-Alb adduct level (p for trend = 0.003), dietary AFB₁ exposure (p for trend < 0.001), and the risk of EPL (p for trend = 0.017). Increased serum AFB₁-Alb adduct level was associated with an increased risk of EPL as well (p for trend < 0.001). In conclusion, corn flour may be an essential source of AFB₁ in Huai'an District, whereas high exposure to AFB₁ is likely to be an important risk factor contributing to the progression of EPL.

Green tea (Camellia sinensis) for the prevention of cancer

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews (2009, Issue 3).Tea is one of the most commonly consumed beverages worldwide. Teas from the plant Camellia sinensis can be grouped into green, black and oolong tea, and drinking habits vary cross-culturally. C sinensis contains polyphenols, one subgroup being catechins. Catechins are powerful antioxidants, and laboratory studies have suggested that these compounds may inhibit cancer cell proliferation. Some experimental and nonexperimental epidemiological studies have suggested that green tea may have cancer-preventative effects.

OBJECTIVES

To assess possible associations between green tea consumption and the risk of cancer incidence and mortality as primary outcomes, and safety data and quality of life as secondary outcomes.

SEARCH METHODS

We searched eligible studies up to January 2019 in CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and reference lists of previous reviews and included studies.

SELECTION CRITERIA

We included all epidemiological studies, experimental (i.e. randomised controlled trials (RCTs)) and nonexperimental (non-randomised studies, i.e. observational studies with both cohort and case-control design) that investigated the association of green tea consumption with cancer risk or quality of life, or both.

DATA COLLECTION AND ANALYSIS

Two or more review authors independently applied the study criteria, extracted data and assessed methodological quality of studies. We summarised the results according to diagnosis of cancer type.

MAIN RESULTS

In this review update, we included in total 142 completed studies (11 experimental and 131 nonexperimental) and two ongoing studies. This is an additional 10 experimental and 85 nonexperimental studies from those included in the previous version of the review. Eleven experimental studies allocated a total of 1795 participants to either green tea extract or placebo, all demonstrating an overall high methodological quality based on 'Risk of bias' assessment. For incident prostate cancer, the summary risk ratio (RR) in the green tea-supplemented participants was 0.50 (95% confidence interval (CI) 0.18 to 1.36), based on three studies and involving 201 participants (low-certainty evidence). The summary RR for gynaecological cancer was 1.50 (95% CI 0.41 to 5.48; 2 studies, 1157 participants; low-certainty evidence). No evidence of effect of non-melanoma skin cancer emerged (summary RR 1.00, 95% CI 0.06 to 15.92; 1 study, 1075 participants; low-certainty evidence). In addition, adverse effects of green tea extract intake were reported, including gastrointestinal disorders, elevation of liver enzymes, and, more rarely, insomnia, raised blood pressure and skin/subcutaneous reactions. Consumption of green tea extracts induced a slight improvement in quality of life, compared with placebo, based on three experimental studies. In nonexperimental studies, we included over 1,100,000 participants from 46 cohort studies and 85 case-control studies, which were on average of intermediate to high methodological quality based on Newcastle-Ottawa Scale 'Risk of bias' assessment. When comparing the highest intake of green tea with the lowest, we found a lower overall cancer incidence (summary RR 0.83, 95% CI 0.65 to 1.07), based on three studies, involving 52,479 participants (low-certainty evidence). Conversely, we found no association between green tea consumption and cancer-related mortality (summary RR 0.99, 95% CI 0.91 to 1.07), based on eight studies and 504,366 participants (low-certainty evidence). For most of the site-specific cancers we observed a decreased RR in the highest category of green tea consumption compared with the lowest one. After stratifying the analysis according to study design, we found strongly conflicting results for some cancer sites: oesophageal, prostate and urinary tract cancer, and leukaemia showed an increased RR in cohort studies and a decreased RR or no difference in case-control studies.

AUTHORS' CONCLUSIONS

Overall, findings from experimental and nonexperimental epidemiological studies yielded inconsistent results, thus providing limited evidence for the beneficial effect of green tea consumption on the overall risk of cancer or on specific cancer sites. Some evidence of a beneficial effect of green tea at some cancer sites emerged from the RCTs and from case-control studies, but their methodological limitations, such as the low number and size of the studies, and the inconsistencies with the results of cohort studies, limit the interpretability of the RR estimates. The studies also indicated the occurrence of several side effects associated with high intakes of green tea. In addition, the majority of included studies were carried out in Asian populations characterised by a high intake of green tea, thus limiting the generalisability of the findings to other populations. Well conducted and adequately powered RCTs would be needed to draw conclusions on the possible beneficial effects of green tea consumption on cancer risk.

Community-Based Upper Gastrointestinal Cancer Screening in a Randomized Controlled Trial: Baseline Results in a Non-high-incidence Area

A cluster-randomized controlled trial (RCT) was conducted to evaluate to the effectiveness of reducing mortality of upper gastrointestinal cancer (UGC) and feasibility of screening through a questionnaire combined with endoscopy in non-high-incidence urban areas in China. The trial design, recruitment performance, and preliminary results from baseline endoscopy are reported. Seventy-five communities in two urban cities with a non-high-incidence of UGC were randomized to a screening endoscopy arm (n = 38) or a control arm (n = 37). In the screening arm, individuals at high risk of UGC underwent endoscopic screening. The primary outcome was the UGC mortality, and secondary outcomes included the UGC detection rate, incidence rate, survival rate, and clinical stage at the time of diagnosis. A total of 10,416 and 9,565 individuals were recruited into the screening and control arms, respectively. The participation rate was 74.3%. In the screening arm, 5,242 individuals (50.3%) were estimated to be high-risk. Among them, 2,388 (45.6%) underwent endoscopic screening. Age and household income were associated with undergoing endoscopy. Three early esophageal cancer (0.13%), one gastric cancer (0.04%), 29 precancerous esophageal lesions (1.21%), and 53 precancerous gastric lesions (2.22%) were detected. Age, sex, a family history of cancer, intake of meat-egg-milk frequently, superficial gastritis, and clinical symptoms of gastric cancer were associated with the presence of precancerous lesions. The detection rate was low using endoscopic screening in non-high-incidence area given the relatively low compliance rate. These findings provide a reference for designing effective community-based UGC screening strategies in non-high-incidence urban areas.

Mycotoxin exposure is associated with increased risk of esophageal squamous cell carcinoma in Huaian area, China

BACKGROUND

Consumption of moldy food has previously been identified as a risk factor for esophageal squamous cell carcinoma (ESCC) in high-risk countries; however, what contributing roles these dietary carcinogenic mycotoxins play in the etiology of ESCC are largely unknown.

METHODS

A mycotoxin biomarker-incorporated, population-based case-control study was performed in Huaian area, Jiangsu Province, one of the two high-risk areas in China. Exposure biomarkers of aflatoxins (AF) and fumonisins (FN) were quantitatively analyzed using HPLC-fluorescence techniques.

RESULTS

Among the cases (n = 190), the median levels of AF biomarker, serum AFB1-lysine adduct, and FN biomarker, urinary FB1, were 1.77 pg/mg albumin and 176.13 pg/mg creatinine, respectively. Among the controls (n = 380), the median levels of AFB1-lysine adduct and urinary FB1 were 1.49 pg/mg albumin and 56.92 pg/mg creatinine, respectively. These mycotoxin exposure biomarker levels were significantly higher in cases as compared to controls (p <  0.05 and 0.01, respectively). An increased risk to ESCC was associated with exposure to both AFB1 and FB1 (p <  0.001 for both).

CONCLUSIONS

Mycotoxin exposure, especially to AFB1 and FB1, was associated with the risk of ESCC, and a greater-than-additive interaction between co-exposures to these two mycotoxins may contribute to the increased risk of ESCC in Huaian area, China.

MTHFR C677T genetic polymorphism in combination with serum vitamin B2, B12 and aberrant DNA methylation of P16 and P53 genes in esophageal squamous cell carcinoma and esophageal precancerous lesions: a case-control study

Background

The study aimed to explore the associations between the interactions of serum vitamin B₂ or B₁₂ levels, aberrant DNA methylation of p16 or p53 and MTHFR C677T polymorphism and the risks of esophageal squamous cell carcinoma (ESCC) and esophageal precancerous lesion (EPL).

Methods

200 ESCC cases, 200 EPL cases and 200 normal controls were matched by age (± 2 years) and gender. Serum vitamin B₂ and B₁₂ levels, MTHFR C677T genetic polymorphisms and the methylation status of genes were assessed. Chi square test, one-way analysis of variance and binary logistic regression were performed.

Results

The lowest quartile of both serum vitamin B₂ and B₁₂ with TT genotype showed significant increased EPL risk (OR = 4.91, 95% CI 1.31-18.35; OR = 6.88, 95% CI 1.10-42.80). The highest quartile of both serum vitamin B₂ and B₁₂ with CC genotype showed significant decreased ESCC risk (OR = 0.16, 95% CI 0.04-0.60; OR = 0.10, 95% CI 0.02-0.46). The ORs of p16 methylation for genotype CT and TT were 1.98 (95% CI 1.01-3.89) and 17.79 (95% CI 2.26-140.22) in EPL, 4.86 (95% CI 2.48-9.50) and 20.40 (95% CI 2.53-164.81) in ESCC, respectively. Similarly, p53 methylation with genotype TT was associated with increased EPL and ESCC risks (OR = 13.28, 95% CI 1.67-105.70; OR = 15.24, 95% CI 1.90-122.62).

Conclusions

The MTHFR C677T genotype and serum vitamin B₂ or B₁₂ levels may interact in ways which associated with the EPL and ESCC risks. The gene-gene interaction suggested that aberrant DNA methyaltion of either p16 or p53 combined with T alleles of MTHFR was associated with increased risks of both EPL and ESCC.

Association Between Alcohol Consumption and Risk of Nasopharyngeal Carcinoma: A Comprehensive Meta-Analysis of Epidemiological Studies

BACKGROUND

Alcohol consumption is increasing all over the world, but whether it is an independent factor affecting the occurrence of nasopharyngeal carcinoma (NPC) is inconsistent in many studies. We aimed to explore the association between alcohol consumption and NPC risk by integrating existing evidence in a meta-analysis.

METHODS

We searched for relevant articles published up to August 2018 in PubMed, Cochrane Library, Web of Science, and China National Knowledge infrastructure (CNKI). The Newcastle-Ottawa scale was used to assess the quality of the included studies. Odds ratios (ORs) or relative risks were pooled to estimate the associations between alcohol consumption and NPC risk.

RESULTS

The meta-analysis of cohort studies showed no significant association between alcohol consumption and NPC, but pooled results from case-control studies indicated that ever drinking increased the probability of NPC versus nondrinking (OR = 1.10; 95% confidence interval [CI]: 1.01, 1.19). As compared with nondrinkers, high-frequency drinking (≥7 times/wk) increased the NPC probability (OR = 1.29; 95% CI: 1.05, 1.53) and low-frequency drinking (<7 times/wk) decreased the probability (OR = 0.77; 95% CI: 0.60, 0.94), as did shorter duration of drinking (<20 years) (OR = 0.64; 95% CI: 0.49, 0.79). On subgroup analyses, significant pooled results were observed for studies with high quality, with hospital-based controls and with adjustment for confounding factors, smoking, age, and sex.

CONCLUSIONS

The risk of NPC may increase with alcohol consumption. Ever drinking increased the risk versus nondrinking. Additionally, high-frequency drinking increased the risk, but low-frequency drinking decreased it to some extent. Further intensive studies based on well-designed methods are needed to examine the association.

Distribution of N-nitrosamines in drinking water and human urinary excretions in high incidence area of esophageal cancer in Huai'an, China

The Huai'an area in Jiangsu Province of East China is an endemic region of esophageal cancer (EC). The regional heterogeneity of EC suggests that the levels of potential carcinogens might vary throughout the environment. It has been suggested that the most likely carcinogens related to EC are a group known as the N-nitrosamines. In this study, we measured the concentrations of nine nitrosamines in drinking water and human urine in two areas in China, one with a high incidence of EC (Huai'an) and one with a low incidence (Nanjing). Among the nine target analytes, N-nitrosodi-n-propylamine (NDPA), N-nitrosodibutylamine (NDBA), N-nitrosopyrrolidine (NPyr), N-nitrosodiethylamine (NDEA) and N-nitrosomorpholine (NMor) occurred at higher concentrations in drinking water in the high incidence area. Inhabitants from the high incidence area also had urinary excretions with significantly higher concentrations of NDEA, NDBA, N-nitrosopiperidine (NPip) and N-nitrosodiphenylamine (NDPhA). These findings indicated that people in the high EC incidence area were exposed to higher levels of nitrosamines. However, the association between the incidence of EC and nitrosamines exposure will need to be evaluated in more detail.

Green Tea Consumption and Esophageal Cancer Risk: A Meta-analysis

Background: The protective role of green tea against cancer is still unknown.Objectives: To investigate the association between green tea consumption and esophageal cancer risk through meta-analysis.Methods: We searched MEDLINE, EMBASE, Web of Science and Cochrane Library for studies on the relationship between green tea and esophageal cancer risk. We assessed heterogeneity (I²) and publication bias (Begg's and Egger's tests). Pooled relative risks (RRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random effects models.Results: A total of 20 studies were included. The RRs for all studies was 0.65 (95% CI: 0.57-0.73), with I² = 75.3% and P = 0. In the subgroup analysis, the following variables showed marked heterogeneity: Asian (RR: 0.64; 95% CI: 0.56-0.73) and non-Asian countries (RR: 0.74; 95% CI: 0.45-1.03), female (RR: 0.55; 95% CI: 0.39-0.71) and male + female (RR: 0.64; 95% CI: 0.54-0.75), case-control study (RR: 0.62; 95% CI: 0.52-0.71), impact factor >3 (RR: 0.65; 95% CI: 0.56-0.75), impact factor <3 (RR: 0.64; 95% CI: 0.48-0.80), Newcastle-Ottawa Scale >7 (RR: 0.82; 95% CI: 0.66-0.97) and Newcastle-Ottawa Scale ≤7 (RR: 0.59; 95% CI: 0.49-0.68).Conclusion: Green tea consumption could be a protective factor for esophageal cancer.

Impacts of Sleep Duration and Snoring on The Risk of Esophageal Squamous Cell Carcinoma

Background Sleep duration and snoring are correlated with tumorigenesis while their associations with esophageal squamous cell carcinoma (ESCC) are unclear. The purpose of this study is to investigate the impacts of night sleep duration and snoring on ESCC risk.

Methods This study included a total of 527 esophageal squamous cell carcinoma patients and 505 gender- and age- matched healthy controls from five hospitals in China. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by conditional logistic regression models.

Results Subjects with sleep duration <7 h (adjusted OR 3.18, 95%CI 1.55-6.53) and regular snoring (adjusted OR 2.56, 95%CI 1.82-3.59) were exposed to high esophageal squamous cell carcinoma risk. After the multivariate models adjusted for body mass index (BMI), the results changed slightly. In the stratified analysis regarding gender, the similar trends occurred in both men and women, and BMI ≥25.0 kg/m² (adjusted OR 0.68, 95%CI 0.48-0.96) was associated with decreased esophageal squamous cell carcinoma risk in men. Additionally, the esophageal squamous cell carcinoma risk attributable to sleep duration <7 h and regular snoring could be completely or partially diminished in subjects with BMI ≥25.0 kg/m².

Conclusion In both genders, short sleep duration (<7h) and regular snoring were significantly related to increased risk of esophageal squamous cell carcinoma independently.

A Distinct Epidemiologic Pattern of Precancerous Lesions of Esophageal Squamous Cell Carcinoma in a High-risk Area of Huai'an, Jiangsu Province, China

Better understanding of esophageal precancerous lesions (EPL) can inform prevention strategies for esophageal squamous cell carcinoma (ESCC). Here, a cross-sectional epidemiologic study based on the Early Diagnosis and Early Treatment Project of Esophageal Cancer database from 2011 to 2017 was performed to fully investigate and characterize the epidemiology of EPL in rural Huai'an District. Data of 11,518 participants ages 35-75 years were collected through face-to-face interviews by questionnaire. Participants underwent a routine endoscopy examination, tissues were biopsied, and diagnosed according to the histologic criteria of dysplasia. Unconditional univariate and multivariate logistic regression analyses were performed to obtain crude and adjusted odds ratios and corresponding 95% confidence intervals, respectively. A total of 667 subjects were diagnosed with EPL. Factors associated with an increased risk of EPL included: drinking shallow well water and surface water, irregular diet, excessive smoking, exposure to secondhand smoke, consumption of corn, corn flour, pickled food, fried food, and hot food, and having a history of digestive system diseases. In addition, liquor use, but not other alcohol types, contributed to risk of EPL. Consumption of deep well water and vegetables, fruits, and animal livers were associated with lower EPL risk. This study suggested a completely distinct pattern that alcohol use plays only a minor role in EPL and excessive tobacco use shows a significant association in rural Huai'an District, while eating habits and environmental exposure may be the dominant factors. This work may be promising to provide scientific evidence to support primary prevention of ESCC in this region.

Inhibitory Effects of (-)-Epigallocatechin-3-gallate on Esophageal Cancer

There is epidemiological evidence showing that drinking green tea can lower the risk of esophageal cancer (EC). The effect is mainly attributed to tea polyphenols and their most abundant component, (−)-epigallocatechin-3-gallate (EGCG). The possible mechanisms of tumorigenesis inhibition of EGCG include its suppressive effects on cancer cell proliferation, angiogenesis, DNA methylation, metastasis and oxidant stress. EGCG modulates multiple signal transduction and metabolic signaling pathways involving in EC. A synergistic effect was also observed when EGCG was used in combination with other treatment methods.

ANXA10 induction by interaction with tumor-associated macrophages promotes the growth of esophageal squamous cell carcinoma

Tumor‐associated macrophages (TAMs) have important roles in the growth, angiogenesis and progression of various tumors. Although we have demonstrated the association of an increased number of infiltrating CD204⁺ TAMs with poor prognosis in esophageal squamous cell carcinomas (ESCCs), the roles of TAMs in ESCC remain unclear. Here, to study the effects of TAMs on the tumor microenvironment of ESCCs, we established a co‐culture assay using a human ESCC cell line and TAM‐like peripheral blood monocyte‐derived macrophages and performed a cDNA microarray analysis between monocultured and co‐cultured ESCC cell lines. Our qRT‐PCR confirmed that in the co‐cultured ESCC cell lines, CYP1A1, DHRS3, ANXA10, KLK6 and CYP1B1 mRNA were highly up‐regulated; AMTN and IGFL1 mRNA were down‐regulated. We observed that the high expression of a calcium‐dependent phospholipid‐binding protein ANXA10 was closely associated with the depth of invasion and high numbers of infiltrating CD68⁺ and CD204⁺ TAMs and poor disease‐free survival (P = 0.0216). We also found ANXA10 promoted the cell growth of ESCC cell lines via the phosphorylation of Akt and Erk1/2 pathways in vitro. These results suggest that ANXA10 induced by the interaction with TAMs in the tumor microenvironment is associated with cell growth and poor prognosis in human ESCC tissues.

PPM1D Functions as Oncogene and is Associated with Poor Prognosis in Esophageal Squamous Cell Carcinoma

Mounting evidence has demonstrated that PPM1D participates in the development and progression of a wide variety of tumors. However, its precise roles in esophageal squamous cell carcinoma (ESCC) remain under investigation. Here, UALCAN, an interactive web-portal to perform the expression analyses of PPM1D using TCGA gene expression data, and PPM1D high expression was exhibited in primary esophageal cancer. Further investigation revealed that PPM1D expression was obviously higher in ESCC tissues than in normal tissues (P < 0.01), which was consistent with the results from real-time qPCR and Western blotting in ESCC tissues and paired normal esophageal tissues. Besides, PPM1D expression was closely correlated with TNM staging, tumor differentiation and lymph node metastasis (P < 0.01), but not related to the patients' gender and age (P > 0.05). Notably, PPM1D expression in metastatic ESCC patients was markedly higher than that in non-metastatic ESCC patients (P < 0.01), and the ESCC patients with high PPM1D expression predicted poor prognosis. Multivariate assay demonstrated that PPM1D and lymph node metastasis were considered as independent prognostic factors for the ESCC patients. These findings suggest PPM1D plays a pivotal important role in onset and progression of ESCC, and may be a new biomarker for metastasis and prognosis of the ESCC patients.

Very hot tea drinking increases esophageal squamous cell carcinoma risk in a high-risk area of China: a population-based case-control study

Background

Previous studies on the association between green tea drinking and esophageal squamous cell carcinoma (ESCC) risk show inconsistent results.

Materials and methods

We conducted a large population-based case–control study from 2010 to 2013 in a high-risk area of China, in which 1,355 ESCC cases and 1,962 controls were recruited. Information on lifelong tea drinking was collected via face-to-face interviews using an electronic structured questionnaire. ORs with 95% CIs were estimated using unconditional logistic regression models.

Results

Most tea drinkers were males and consumed exclusively green tea. After adjustment for potential confounders, among men the OR of ever green tea drinking for ESCC risk was 1.52 (95% CI: 1.24–1.85), compared with never tea drinking. The excess risk increased monotonically with earlier age at starting, longer duration, more intensity, and accumulation of tea drinking. The OR of drinking very hot green tea for ESCC risk was 2.15 (95% CI: 1.52–3.05), compared with never drinking tea. For accumulation of tea drinking and the risk of ESCC, a non-linear relationship was observed. Before the accumulation of tea drinking reached 5 L/day*years, drinking tea showed a mild protective effect; then the ORs sharply increased to around 2.0 from 5 L/day*years to 25 L/day*years, and leveled off thereafter. The non-linear relationship was further modified by tea temperature. The joint effect of tea drinking and alcohol consumption on ESCC risk was also significant (P=0.019).

Conclusion

Very hot tea drinking significantly increases the risk of ESCC among Chinese men, which is particularly evident among alcohol drinkers.

Occurrence and potential human health risks of semi-volatile organic compounds in drinking water from cities along the Chinese coastland of the Yellow Sea

Semi-volatile organic compounds (SVOCs) in drinking water have been considered a severe threat to public health worldwide. However, SVOC contamination and the associated human health risks of the drinking water from cities along tributaries of the Yangtze River and Huaihe River in China have been seldom reported. Here, we focused on the occurrence and distribution of a series of SVOCs, mainly including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and phthalate esters (PAEs), in drinking water of this region. In brief, a total of 31 SVOCs were detectable in all of the drinking water samples, and the total concentrations ranged from 0.92 ng/L to 266.16 ng/L in March and from 24.82 ng/L to 643.93 ng/L in August, with the highest concentrations in Dongtai (DT) and Xinghua (XH), respectively. Spatial and temporal differences of the SVOCs were also observed in drinking water samples, demonstrating the linkage between pollutant profiles and geographical locations, as well as exogenous wastewater discharge. Moreover, PAEs occupied 79.17-100.00% of the total concentrations of SVOCs in drinking water samples collected from the tributaries of the Yangtze River in March, while OCPs were the predominant SVOCs in most of drinking water samples from the tributaries of the Huaihe River. The human health assessment indicated that SVOCs posed negligible non-carcinogenic risks, but residents living in DT, Dafeng (DF), Chengdong (CD), Guanyun (GY) and Lianyungang (LY) may suffer carcinogenic health risks, which could be mainly induced by benzene hexachloride and heptachlor in August.

Elevated levels of serum nidogen-2 in esophageal squamous cell carcinoma

BACKGROUND

Nidogen-2 (NID2), a secretory basement membrane protein, has been implicated as a potential biomarker in ovarian cancer and hepatocellular carcinoma.

OBJECTIVE

In this study, we aimed to investigate the utility of detecting serum NID2 levels for identification of esophageal squamous cell carcinoma (ESCC) patients and prediction of poor survival outcome.

METHODS

Using an in-house NID2 enzyme-linked immunosorbent assay (ELISA), serum samples from 101 ESCC patients and 50 healthy controls were screened for their NID2 levels.

RESULTS

The serum NID2 levels in ESCC patients (median 24.4 μg/L) are significantly higher (p= 4.3e-09) than that of the healthy controls (median 15.85 μg/L). The receiver operating characteristic (ROC) curve demonstrated an area under the curve of 0.756. At the threshold of 17.95 μg/L, the sensitivity and specificity achieved are 0.76 and 0.63, respectively. Kaplan-Meier survival analysis revealed that patients with high serum NID2 levels (⩾ 32.6 μg/L) have significantly higher risk of death (HR = 1.984, 95% CI: 1.175-3.349; log-rank p-value = 0.012) compared to those with low serum NID2 levels (< 20.0 μg/L).

CONCLUSIONS

In conclusion, we show that detecting the elevation of serum NID2 levels has potential diagnostic and prognostic value for ESCC patients.

A genetic polymorphism in the CYP1B1 gene in patients with squamous cell carcinoma of the esophagus: an Iranian Mashhad cohort study recruited over 10 years

Aim: Esophageal cancer is the eighth most common cancer globally and the seventh most common cause of cancer-related deaths in men. Recent studies have shown that CYP450, family 1, subfamily B, polypeptide 1, which plays a role in the metabolism of xenobiotics, is associated with several cancers. Therefore, in the present study we investigated the association between a genetic variant, CYP1B1-rs1056836 gene, with the clinical characteristics of patients with squamous cell carcinoma of the esophagus (ESCC). Method: In this study, 117 patients with ESCC and 208 healthy controls were recruited. DNA was extracted and genotyped using real-time PCR-based TaqMan. Kaplan–Meier curves were utilized to assess overall and progression-free survival. To evaluate the relationship between clinicopathological data, genotypic frequencies, disease prognosis and survival, Pearson's χ2 and t-test were used. Logistic regression was utilized to assess the association between the risk of ESCC and genotypes. Results: The genotypic frequency for GG, GC and CC were 58.6, 29.8 and 11.5%, respectively, in the healthy subjects and 51.8, 36.14 and 12% in the ESCC group. An association between the GG genotype and stage of ESCC was found. Also, statistically significant results were not found for this variation and risk of ESCC. Conclusion: Our findings suggest a relationship between the CYP1B1-rs1056836 genetic polymorphism and clinical features of ESCC, supporting further studies in larger populations in different ethnic groups, taking into account potentially important environmental factors such as diet.

Smoking and alcohol drinking in relation to the risk of esophageal squamous cell carcinoma: A population-based case-control study in China

Previous results regarding the associations between esophageal squamous-cell carcinoma (ESCC) risk and smoking/alcohol drinking in high-risk areas are inconsistent. We performed a large population-based case-control study from 2010 to 2013 in a high-incidence area of China, and enrolled 1353 ESCC cases and 1961 controls. Data regarding smoking and alcohol drinking were collected via face-to-face interviews using a structured questionnaire. Odd ratios (ORs) with 95% confidence intervals (CIs) were estimated using unconditional logistic regression models. After adjusting for alcohol drinking and other potential confounders, male heavy smokers (i.e., those who started smoked more than 20 cigarettes per day or 40 pack-years, or started smoking early), showed a moderately increased risk for ESCC; however, current smoking was not associated with an increased risk. Alcohol drinking among males significantly increased the risk for ESCC (OR = 2.20, 95%CI:1.79~2.70). We observed increasing excess ESCC risks with decreasing age at behavior initiation as well as with increasing duration and intensity of alcohol intake, which were particularly evident among current smokers. In contrast, neither smoking nor alcohol drinking was not associated with ESCC risk among females. In conclusion, alcohol drinking shows a monotonic dose-response relationship with ESCC risk among men, and this relationship is particularly evident among smokers.

Sitting time and occupational and recreational physical activity in relation to the risk of esophageal squamous cell carcinoma

Backgrounds

Sitting time and physical activity are associated with cancer risk; however, their roles in the development of esophageal squamous cell carcinoma (ESCC) are inconclusive. This study aimed to investigate the effects of total sitting time, occupational activity time (OAT), and recreational activity time (RAT) on ESCC risk.

Methods

Five hundred fifty-seven ESCC patients and 543 healthy controls matched by sex and age were recruited for this study. Conditional logistic regression was performed to obtain odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Longer total sitting time (adjusted OR [AOR] 2.54, 95% CI 1.58–4.09) and longer OAT (AOR 2.90, 95% CI 2.11–3.99) were associated with higher ESCC risk, while longer RAT (AOR 0.27, 95% CI 0.19–0.38) could reduce ESCC risk. When the body mass index was incorporated into the multivariable models, the results changed slightly. In risk estimation according to sex, the same trends were observed in both men and women. Furthermore, longer RAT could completely or partially diminish the impacts of longer sitting time and OAT on increasing ESCC risk.

Conclusion

Long sitting time and long OAT can increase the risk of ESCC, while long RAT is significantly associated with decreased ESCC risk.

Preliminary evaluation for Bit1 as a potential biomarker for squamous cell carcinoma and adenocarcinoma of esophagus

Mounting evidence has demonstrated that Bit1 has been investigated as an etiological factor for certain cancers, including esophageal squamous cell carcinoma reported in our previous study, but data regarding possible roles of Bit1 in esophageal squamous cell carcinoma and esophageal adenocarcinoma remain to be elucidated. The purpose of this study was to examine whether Bit1 can be a novel diagnostic marker for the patients with esophageal squamous cell carcinoma and esophageal adenocarcinoma. The results revealed that Bit1 level in esophageal squamous cell carcinoma was significantly higher than that in esophageal adenocarcinoma tissues ( p < 0.05); notably, Bit1 level in esophageal adenocarcinoma tissues was lower than that in paired normal tissues but no difference was found ( p > 0.05). Bit1 expression patterns were completely in accordance with matrix metalloproteinase 2 and Bcl-2 in esophageal squamous cell carcinoma and esophageal adenocarcinoma. In addition, Bit1, Bcl-2, and matrix metalloproteinase 2 expression patterns in different differentiated esophageal squamous cell carcinoma were higher than those in corresponding normal esophageal tissues. Bit1 expression in poorly differentiated esophageal squamous cell carcinoma was significantly higher than that in normal esophageal tissues ( p < 0.05) but not in moderately and well-differentiated esophageal squamous cell carcinoma. Matrix metalloproteinase 2 expression patterns in poorly and moderately differentiated esophageal squamous cell carcinoma were significantly higher than those in corresponding normal esophageal tissues ( p < 0.01) but not in well-differentiated esophageal squamous cell carcinoma tissue ( p > 0.05). Bcl-2 expression patterns in various differentiated esophageal squamous cell carcinoma were higher than those in corresponding normal esophageal tissues with no statistical differences ( p > 0.05). Importantly, Bit1 expression was positively correlated with both matrix metalloproteinase 2 and Bcl-2 expression in esophageal squamous cell carcinoma and esophageal adenocarcinoma tissues ( p < 0.05). Collectively, these preliminary data support further investigation of Bit1 as an important diagnostic factor for esophageal squamous cell carcinoma and esophageal adenocarcinoma.

Estrogen Receptors in Regulating Cell Proliferation of Esophageal Squamous Cell Carcinoma: Involvement of Intracellular Ca2+ Signaling

Esophageal cancer is a deadly disease in the esophagus with a poor prognosis. Over 90 % of esophageal cancer is esophageal squamous cell carcinoma (ESCC) and its pathogenic mechanisms remain unclear. Epidemiology study found a strong gender difference with a sex ratio of 8-9:1 in favor of males, but the molecular mechanisms for so striking gender difference are poorly understood so far. In the present study, we demonstrated the expression of estrogen receptors in human ESCC cells. 17β-E2 but not 17α-E2 was found to dose-dependently suppress the cell proliferation of human ESCC cells, which was attenuated by estrogen receptor antagonist ICI1 82,780. Furthermore, 17β -E2 but not 17α-E2 10 nM markedly induced both intracellular Ca²⁺ release and extracellular Ca²⁺ entry into ESCC cells, which was again attenuated by estrogen receptor antagonist ICI182,780. Taken together, our data clearly demonstrate that estrogen exerts anti-proliferative action on human ESCC cells likely through estrogen receptor-Ca²⁺ signaling pathway, which may provide a reasonable explanation on the striking male predominance of ESCC.

Epidemiological evidence on environmental tobacco smoke and cancers other than lung or breast

We reviewed 87 epidemiological studies relating environmental tobacco smoke (ETS) exposure to risk of cancer other than lung or breast in never smoking adults. This updates a 2002 review which also considered breast cancer. Meta-analysis showed no significant relationship with ETS for nasopharynx cancer, head and neck cancer, various digestive cancers (stomach, rectum, colorectal, liver, pancreas), or cancers of endometrium, ovary, bladder and brain. For some cancers (including oesophagus, colon, gall bladder and lymphoma) more limited data did not suggest a relationship. An increased cervix cancer risk (RR 1.58, 95%CI 1.29-1.93, n = 17 independent estimates), reducing to 1.29 (95%CI 1.01-1.65) after restriction to five estimates adjusting for HPV infection or sexual activity suggests a causal relationship, as do associations with nasosinus cancer observed in 2002 (no new studies since), and less so kidney cancer (RR 1.33, 95%CI 1.04-1.70, n = 6). A weaker association with total cancer (RR 1.13, 95%CI 1.03-1.35, n = 19) based on heterogeneous data is inconclusive. Inadequate confounder control, recall bias, publication bias, and occasional reports of implausibly large RRs in individual studies contribute to our conclusion that the epidemiological evidence does not convincingly demonstrate that ETS exposure causes any of the cancers studied.

Alcohol consumption and corresponding factors: A novel perspective on the risk factors of esophageal cancer

Esophageal cancer is the eighth most common type of cancer in the world, and the sixth most common cause of mortality from cancer. Alcohol consumption is the major risk factor for esophageal cancer, due to the worldwide prevalence and high carcinogenicity of the ethanol metabolite. In epidemiological studies, the efficiency of alcohol intake to enhance the risk of esophageal cancer is altered by daily ethanol consumption, type of alcoholic beverages ingested, time since quitting drinking, age of drinking initiation, differences in population and subtypes of esophageal cancer. Corresponding factors, including gene polymorphisms, tobacco smoking, oral microorganisms and folate deficiency, reveal a synergistic effect in concurrent alcohol users that may lead to an increased risk of developing esophageal cancer. Consequently, esophageal cancer prevention involves multiple aspects, including quitting drinking and smoking, maintaining an adequate oral health and ingesting adequate quantities of folate, particularly in genetically high-risk populations.

Cancer prevention and control: alarming challenges in China

China is geographically the third largest country in the world and the most populated low-to-middle-income country. Cancer incidence and mortality rates for some cancers in the USA and European countries have steadily decreased over the last decades, whereas the incidence and mortality of certain cancers in China have been increasing at an alarming speed. Rapid industrialization and urbanization in China have been accompanied by incredible changes in lifestyle and environment combined with an aging population. Mortality caused by lung, colorectal and breast cancers has been steadily increasing, whereas cancer mortality from gastric, esophageal and cervical tumors has tended to decrease. Similar to what has occurred in the United States, unhealthy lifestyles in China, including heavy smoking and poor diet combined with pollution, have contributed to increased cancer risk. China is facing many challenges in cancer treatment and prevention for the general population. The major areas that need to be addressed in the control of cancer in China include cancers associated with environmental pollution, tobacco use, occupational carcinogens, infection, excessive alcohol consumption, dietary deficiencies and obesity. In this perspective, we review the problems in each area and suggest ideas for future directions in cancer research and strategies and actions to reduce the incidence of cancer in China.

Presence of Porphyromonas gingivalis in esophagus and its association with the clinicopathological characteristics and survival in patients with esophageal cancer

Background

Mounting evidence suggests a causal relationship between specific bacterial infections and the development of certain malignancies. However, the possible role of the keystone periodontal pathogen, Porphyromonas gingivalis, in esophageal squamous cell carcinoma (ESCC) remains unknown. Therefore, we examined the presence of P. gingivalis in esophageal mucosa, and the relationship between P. gingivalis infection and the diagnosis and prognosis of ESCC.

Methods

The presence of P. gingivalis in the esophageal tissues from ESCC patients and normal controls was examined by immunohistochemistry using antibodies targeting whole bacteria and its unique secreted protease, the gingipain Kgp. qRT-PCR was used as a confirmatory approach to detect P. gingivalis 16S rDNA. Clinicopathologic characteristics were collected to analyze the relationship between P. gingivalis infection and development of ESCC.

Results

P. gingivalis was detected immunohistochemically in 61 % of cancerous tissues, 12 % of adjacent tissues and was undetected in normal esophageal mucosa. A similar distribution of lysine-specific gingipain, a catalytic endoprotease uniquely secreted by P. gingivalis, and P. gingivalis 16S rDNA was also observed. Moreover, statistic correlations showed P. gingivalis infection was positively associated with multiple clinicopathologic characteristics, including differentiation status, metastasis, and overall survival rate.

Conclusion

These findings demonstrate for the first time that P. gingivalis infects the epithelium of the esophagus of ESCC patients, establish an association between infection with P. gingivalis and the progression of ESCC, and suggest P. gingivalis infection could be a biomarker for this disease. More importantly, these data, if confirmed, indicate that eradication of a common oral pathogen could potentially contribute to a reduction in the overall ESCC burden.

Electronic supplementary material

The online version of this article (doi:10.1186/s13027-016-0049-x) contains supplementary material, which is available to authorized users.

Secondhand Smoking and the Risk of Esophageal Squamous Cell Carcinoma in a High Incidence Region, Kashmir, India: A Case-control-observational Study

Studies have associated secondhand smoking (SHS) with cancers of the lung, larynx, and pharynx. Only a few studies have examined the association between SHS and esophageal squamous cell carcinoma (ESCC) and the findings are inconclusive. We aimed to investigate the association between SHS and risk of ESCC in a case-control study in Kashmir, where the incidence of ESCC is high. We recruited 703 histopathologically confirmed ESCC cases and 1664 hospital-based controls individually matched to the cases for age, sex, and district of residence. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using conditional logistic regression models. Among never-tobacco users, the ORs for the association between SHS and ESCC risk were above unity with ever exposure to SHS (OR = 1.32; 95% CI, 0.43-4.02) and exposure to SHS for > 14 h/wk (median value) (OR = 2.69; 95% CI, 0.75-20.65). In the analysis of data from all participants, the OR (95% CI) for the association between SHS and ESCC was (OR = 1.02; 95% CI, 0.53-1.93) for SHS ≤ 14 h/wk and (OR = 1.91; 95% CI, 0.75-4.89) for SHS >14 h/wk in the models adjusted for tobacco use and several other potential confounding factors. We found an indication of increased risk of ESCC associated with exposure to SHS. Studies with larger numbers of SHS-exposed never tobacco users are required to further examine this association.

Gene-environment interactions in esophageal cancer

Esophageal cancer (EC) is one of the most common malignancies in low- and medium-income countries and represents a disease of public health importance because of its poor prognosis and high mortality rate in these regions. The striking variation in the prevalence of EC among different ethnic groups suggests a significant contribution of population-specific environmental and dietary factors to susceptibility to the disease. Although individuals within a demarcated geographical area are exposed to the same environment and share similar dietary habits, not all of them will develop the disease; thus genetic susceptibility to environmental risk factors may play a key role in the development of EC. A wide range of xenobiotic-metabolizing enzymes are responsible for the metabolism of carcinogens introduced via the diet or inhaled from the environment. Such dietary or environmental carcinogens can bind to DNA, resulting in mutations that may lead to carcinogenesis. Genes involved in the biosynthesis of these enzymes are all subject to genetic polymorphisms that can lead to altered expression or activity of the encoded proteins. Genetic polymorphisms may, therefore, act as molecular biomarkers that can provide important predictive information about carcinogenesis. The aim of this review is to discuss our current knowledge on the genetic risk factors associated with the development of EC in different populations; it addresses mainly the topics of genetic polymorphisms, gene-environment interactions, and carcinogenesis. We have reviewed the published data on genetic polymorphisms of enzymes involved in the metabolism of xenobiotics and discuss some of the potential gene-environment interactions underlying esophageal carcinogenesis. The main enzymes discussed in this review are the glutathione S-transferases (GSTs), N-acetyltransferases (NATs), cytochrome P450s (CYPs), sulfotransferases (SULTs), UDP-glucuronosyltransferases (UGTs), and epoxide hydrolases (EHs), all of which have key roles in the detoxification of environmental and dietary carcinogens. Finally, we discuss recent advances in the study of genetic polymorphisms associated with EC risk, specifically with regard to genome-wide association studies, and examine possible challenges of case-control studies that need to be addressed to better understand the interaction between genetic and environmental factors in esophageal carcinogenesis.

Association between dietary behavior and esophageal squamous cell carcinoma in Yanting

BACKGROUND

Yanting is one of high risk areas for esophageal cancer and the screening program was therefore initiated there. This study was aimed to investigate the dietary behaviors on the risk of esophageal squamous cell carcinoma (ESCC), among the individuals with normal and abnormal esophagus mucosa.

MATERIALS AND METHODS

A frequency matched case-controls study was proposed to estimate the different distribution of dietary behavior between individuals of control, esophagitis and cancer groups. Cancer cases were selected from hospitals. Esophagitis cases and controls were selected from screening population for ESCC. Health workers collected data for 1 year prior to interview, in terms of length of finishing a meal, temperature of eaten food and interval between water boiling and drinking. Chi-square, Kruskal-Wallis tests and unconditional logistic regression model were used to estimate differences and associations between groups.

RESULTS

Compared with controls, length of finishing a meal≥15 mins was related to a reduced OR for cancer (OR=0.46, 95%CI, 0.22- 0.97) and even compared with cases of esophagitis, the OR of cancer was reduced to 0.30 (95%CI, 0.13-0.72). The OR for often eating food at a high temperature was 2.48 (95%CI 1.06, 5.82) for ESCC as compared with controls. Interval between water boiling and drinking of ≥10 mins was associated with lower risk of cancer: the OR was 0.18 compared with controls and 0.49 with esophagitis cases (p<0.05).

CONCLUSIONS

Length of eating food≥15 mins and interval between water boiling and drinking ≥10 mins are potentially related to reduced risk of esophageal SCC, compared with individuals with normal and abnormal esophageal mucosa. Recommendations to Yanting residents to change their dietary behaviors should be made in order to reduce cancer risk.

Association between glutathione S-transferases P1 Ile105Val polymorphism and susceptibility to esophageal cancer: evidence from 20 case-control studies

Available epidemiological studies had estimated the correlation between glutathione S-transferases P1 (GSTP1) Ile105Val polymorphism and esophageal cancer (EC) risk. However, the conclusions were controversial and inconclusive. An updated meta-analysis was conducted to explore whether GSTP1 polymorphism could be contributed to the EC risk. Ultimately, a total of 2,992 cases and 4,758 controls from 20 previous studies were included. Crude odds ratios (ORs) with 95 % confidence intervals (95 % CIs) were used to assess the strength of the associations. Pooled results suggested that GSTP1 Ile105Val polymorphism significantly increased the risk of developing EC in Caucasians under three genetic models (G vs. A, OR 1.146, 95 % CI 1.031-1.275, P = 0.012, I(2) = 30.40 %; GA vs. AA, OR 1.208, 95 % CI 1.036-1.408, P = 0.016, I(2) = 50.30 %; GG+GA vs. AA, OR 1.219, 95 % CI 1.053-1.410, P = 0.008, I(2) = 44.50 %). However, no significant correlation was found in Asians, African and mixed ethnicities analyses. Moreover, similar results were detected for any genetic model in esophageal squamous cell carcinoma and esophageal adenocarcinoma when stratifying for pathologic types. This meta-analysis provides new evidences that GSTP1 Ile105Val gene polymorphism contributes to EC susceptibility in Caucasians.

The role of epoxide hydrolases in health and disease

Epoxide hydrolases (EH) are ubiquitously expressed in all living organisms and in almost all organs and tissues. They are mainly subdivided into microsomal and soluble EH and catalyze the hydration of epoxides, three-membered-cyclic ethers, to their corresponding dihydrodiols. Owning to the high chemical reactivity of xenobiotic epoxides, microsomal EH is considered protective enzyme against mutagenic and carcinogenic initiation. Nevertheless, several endogenously produced epoxides of fatty acids function as important regulatory mediators. By mediating the formation of cytotoxic dihydrodiol fatty acids on the expense of cytoprotective epoxides of fatty acids, soluble EH is considered to have cytotoxic activity. Indeed, the attenuation of microsomal EH, achieved by chemical inhibitors or preexists due to specific genetic polymorphisms, is linked to the aggravation of the toxicity of xenobiotics, as well as the risk of cancer and inflammatory diseases, whereas soluble EH inhibition has been emerged as a promising intervention against several diseases, most importantly cardiovascular, lung and metabolic diseases. However, there is reportedly a significant overlap in substrate selectivity between microsomal and soluble EH. In addition, microsomal and soluble EH were found to have the same catalytic triad and identical molecular mechanism. Consequently, the physiological functions of microsomal and soluble EH are also overlapped. Thus, studying the biological effects of microsomal or soluble EH alterations needs to include the effects on both the metabolism of reactive metabolites, as well as epoxides of fatty acids. This review focuses on the multifaceted role of EH in the metabolism of xenobiotic and endogenous epoxides and the impact of EH modulations.

Fatty and lean red meat consumption in China: differential association with Chinese abdominal obesity

AIM

We examined the longitudinal association between red meat (RM) consumption and the risk of abdominal obesity in Chinese adults.

METHODS AND RESULTS

Our data are from 16,822 adults aged 18-75 in the China Health and Nutrition Survey from 1993 to 2011. We assessed RM intake with three 24-h dietary recalls. We defined abdominal obesity as a waist circumference (WC) ≥85 centimeters (cm) for men and ≥80 cm for women. Multilevel mixed-effect regression models showed that men experienced WC increases of 0.74 cm (95% confidence interval [CI]: 0.39-1.09) from a higher total intake of fresh RM and 0.59 cm (95% CI: 0.24-0. 95) from a higher intake of fatty fresh RM but 0.14 cm (95% CI: -0.39 to 0.66) from a higher intake of lean fresh RM in the top quartile versus non-consumers when adjusted for potential confounders. In contrast, after additional adjustment for baseline WC, the odds ratios of abdominal obesity in men were attenuated for total fresh RM (1.25 [95% CI: 1.06-1.47]) and fatty fresh RM (1.22 [95% CI: 1.03-1.44]) but were still not affected by lean fresh RM (0.95 [95% CI: 0.75-1.22]). Women also showed a positive association of fatty fresh RM intake with abdominal obesity.

CONCLUSION

Greater intake of fatty fresh RM was significantly associated with higher WC (men only) and abdominal obesity risk in Chinese adults. The gender-specific differential association of fatty versus lean fresh RM warrants further study.

Lack of association between EPHX1 polymorphism and esophageal cancer risk: evidence from meta-analysis

The microsomal epoxide hydrolase 1 (EPHX1) Tyr113His and His139Arg polymorphisms have been reported to be associated with esophageal cancer (EC) risk, yet the results of these previous results have been inconsistent or controversial. The objective of this study was to explore whether the EPHX1 Tyr113His and His139Arg polymorphisms confer risk to EC. The relevant studies were identified through a search of PubMed, Excerpta Medica Database (Embase), Elsevier Science Direct, and Chinese Biomedical Literature Database until May 2013. The association between the EPHX1 Tyr113His and His139Arg polymorphisms and EC risk was pooled by odds ratios (ORs) together with their 95% confidence intervals (95%CIs). A total of eight case-control studies with 1163 EC patients and 1868 controls (seven studies for both Tyr113His and His139Arg polymorphisms, one study only for Tyr113His polymorphism) were eventually identified. We found no association between EPHX1 Tyr113His and His139Arg polymorphisms and EC risk in overall population (For Tyr113His: His vs. Tyr: OR = 1.05, 95%CI = 0.95-1.15, P = 0.379; His/His vs. Tyr/Tyr: OR = 1.04, 95%CI = 0.88-1.22, P = 0.208; His/Tyr vs. Tyr/Tyr: OR = 0.96, 95%CI = 0.80-1.15, P = 0.577; His/His vs. His/Tyr + Tyr/Tyr: OR = 1.10, 95%CI = 0.96-1.26, P = 0.164; His/His + His/Tyr vs. Tyr/Tyr: OR = 1.01, 95%CI = 0.90-1.12, P = 0.543. For His139Arg: Arg vs. His: OR = 1.04, 95%CI = 0.94-1.14, P = 0.465; Arg/Arg vs. His/His: OR = 1.06, 95%CI = 0.91-1.24, P = 0.470; Arg/His vs. His/His: OR = 1.03, 95%CI = 0.91-1.16, P = 0.673; Arg/Arg vs. Arg/His + His/His: OR = 1.04, 95%CI = 0.85-1.27, P = 0.708; Arg/Arg + Arg/His vs. His/His: OR = 1.02, 95%CI = 0.93-1.13, P = 0.617). In subgroup analysis based on ethnicity, significant association has been found in neither EPHX1 Tyr113His nor His139Arg polymorphism. The current meta-analysis suggests no evidence of association between the EPHX1 polymorphism and EC risk.

Dinner-to-bed time and post-dinner walk: new potential independent factors in esophageal cancer development

PURPOSE

Esophageal squamous cell carcinoma (ESCC) remains a significant cause of morbidity and mortality worldwide. The aim of the study was to investigate the effects of shorter dinner-to-bed time and post-dinner walk on ESCC risk.

METHODS

A matched case-control study with 232 ESCC patients and 286 age- and gender-matched healthy controls enrolled was conducted. Conditional logistic regression was used to calculated odds ratio (OR) and 95 % confidence intervals (95 % CI).

RESULTS

The adjusted ORs of ESCC for subjects with shorter dinner-to-bed time (<3 h) were 2.84 (95 % CI 1.64-4.29), relative to those with longer dinner-to-bed time (≥4 h). While post-dinner walk was associated with a decreased ESCC risk (adjusted OR 0.64; 95 % CI 0.41-0.89). What's more, when reflux symptom was added into the multivariate models, risk estimate for shorter dinner-to-bed time still remained statistically significant (p = 0.003), and risk estimate for post-dinner walk changed slightly. In the subgroup analysis stratified by post-dinner walk, subjects with shorter dinner-to-bed time experienced similar risk (adjusted ORs 2.71 vs. 2.82).

CONCLUSIONS

Shorter dinner-to-bed time is a potential risk factor for ESCC and post-dinner walk is a protective factor, providing evidence for the effect of lifestyle factors on ESCC risk.

Evidence for the aetiology of human papillomavirus in oesophageal squamous cell carcinoma in the Chinese population: a meta-analysis

OBJECTIVES

We aimed to conduct a meta-analysis of human papillomavirus (HPV) as a risk factor for oesophageal squamous cell carcinoma (OSCC) in China, using all eligible studies published in the English and Chinese language literature.

DESIGN

The random effect model was used to analyse the pooled OR. The I(2) and Q tests were included in the subgroup analyses.

SETTING

Literature searches of databases including MEDLINE, PUBMED, EMBASE and Chinese National Knowledge Infrastructure (CNKI) and other available resources were performed to retrieve studies investigating OSCC tissue from Chinese participants for the presence of HPV DNA.

PRIMARY OUTCOME MEASURE

A collective analysis of OSCC cases and control specimens was carried out from 15 case-control studies (6 in the English language and 9 in the Chinese language) for HPV prevalence.

RESULTS

Of a total of 1177 OSCC and 1648 oesophageal control samples, 55% (642/1177) of cancer specimens and 27% (445/1648) of control samples were positive for HPV DNA. A positive strong association between HPV DNA and OSCC was observed among the included studies, with a pooled OR of 3.69 (95% CI 2.74 to 4.96). Heterogeneity and publication bias were not observed in the analysis. Subgroup analyses of the included studies also supported the measure of association of causal links between HPV and OSCC.

CONCLUSIONS

This meta-analysis provides the strongest evidence until now of an association between HPV and OSCC in the Chinese population. China has a high burden of OSCC, making this an important research finding. A strength and new contribution of this study is combining data from the English and Chinese language literature to analyse all studies conducted in China. These findings may inform the population level use of prophylactic HPV vaccination to reduce the burden of OSCC in China.

Association between CYP1A1 polymorphisms and esophageal cancer: a meta-analysis

Cytochrome P4501A1 (CYP1A1) enzyme is a member of the CYP superfamily of enzymes. CYP1A1 A2455G and T3801C are two most commonly studied polymorphisms loci. Previous studies have reported that CYP1A1 polymorphisms increase esophageal cancer (EC) risk. However, the results remain controversial and ambiguous. To further investigate the association between CYP1A1 polymorphisms (A2455G and T3801C) and EC risk. A meta-analysis was performed to investigate the association between CYP1A1 polymorphisms and EC risk. A total of 13 articles (A2455G and T3801C: 2 papers, A2455G: 8 papers, T3801C: 3 papers) from the PubMed containing information on the CYP1A1 polymorphisms and EC were included in this meta-analysis, with summational sample size of 1,881 EC cases and 3,786 controls. Stratified analysis was performed to evaluate the ethnicity (Caucasians and Asian) and histopathology type (esophageal squamous cell carcinoma and esophageal adenocarcinoma) effect. No obvious publication bias in the two polymorphisms was observed. Our meta-analysis revealed a significant association between the A2455G polymorphism and EC (OR = 1.55 per A allele, 95 % CI 1.29-1.85, P < 0.001). Stratification analysis by ethnicity and histopathology type showed significant association in the population of Asian origin (OR = 1.55, 95 % CI 1.28-1.89, P < 0.001) and in histopathology type of ESCC (OR = 1.40, 95 % CI 1.19-1.65, P < 0.001). We didn't observe the significant association between CYP1A1 T3801C polymorphism and EC. We observed a difference of allele frequencies between Caucasian and Asian population in the meta-analysis. The allele frequencies in our meta-analysis were consistent with the allele frequencies in 1000 Genome Project. Our meta-analysis demonstrated distinct evidence that CYP1A1 A2455G polymorphism was associated with the risk of EC.

Effects of green tea, black tea, and coffee consumption on the risk of esophageal cancer: a systematic review and meta-analysis of observational studies

Epidemiological studies regarding the associations of tea and coffee consumption with esophageal cancer (EC) risk are still inconsistent and this meta-analysis was conducted to examine these associations. PubMed, ISI -Web of Science, China National Knowledge Infrastructure (CNKI), and Chinese VIP database up to October 2011 were searched and manual search for reference lists of relevant studies were conducted. Random effects model was used to pool the odds ratios (OR). Twenty-four case-control and cohort studies with 7376 EC cases were included in this meta-analysis. The pooled OR of EC was 0.77 [95% confidence intervals (95% CI): 0.57, 1.04] for highest vs. non/lowest green tea consumption; but it was statistically significant for case-control studies (OR = 0.70; 95% CI: 0.51, 0.96) and for studies conducted in China (OR = 0.64; 95% CI: 0.44, 0.95). No significant association was observed for the highest vs. non/lowest black tea consumption against EC risk (OR = 1.35; 95% CI: 0.86, 2.11). A borderline significantly inverse association of highest vs. non/lowest coffee consumption against EC risk was found (OR = 0.88; 95% CI: 0.76, 1.01). In conclusion, our data showed that both green tea and coffee consumption, but not black tea consumption, have protective effects on EC.

Null genotype of GSTT1 contributes to esophageal cancer risk in Asian populations: evidence from a meta-analysis

BACKGROUND/AIMS

Glutathione S-transferase T1 (GSTT1), a phase-II enzyme, plays an important role in detoxification of carcinogen electrophiles. Many studies have investigated the association between GSTT1 polymorphism and esophageal cancer risk in Asian populations, but its actual impact is not clear owing to apparent inconsistencies among those studies. Thus, a meta-analysis was performed to explore the effect of GSTT1 polymorphism on the risk of developing esophageal cancer.

METHODS

A literature search of PubMed, Embase, and Wanfang databases up to August 2012 was conducted and 15 eligible papers were finally selected, involving a total of 1,626 esophageal cancer cases and 2,216 controls. We used the pooled odds ratio (OR) with its corresponding 95% confidence interval (95%CI) to estimate the association of GSTT1 polymorphism with esophageal cancer risk. Subgroup analyses and sensitivity analyses were performed to further identify the association.

RESULTS

Meta-analysis of total studies showed the null genotype of GSTT1 was significantly associated with an increased risk of esophageal cancer in Asians (OR=1.26, 95%CI=1.05-1.52, POR=0.015, I2=42.7%). Subgroup analyses by sample size and countries also identified a significant association. Sensitivity analysis further demonstrated a relationship of GSTT1 polymorphism to esophageal cancer risk in Asians.

CONCLUSIONS

The present meta-analysis of available data showed a significant association between the null genotype of GSTT1 and an increased risk of esophageal cancer in Asians, particularly in China.

No role for glutathione S-transferase genotypes in Caucasian esophageal squamous cell or adenocarcinoma etiology: an European case-control study

BACKGROUND

Identifying and monitoring high-risk patients can aid the prevention of esophageal cancer (EC). The interaction of environmental risk factor exposure and genetic susceptibility may contribute to the etiology of EC. Biotransformation enzymes such as Glutathione S-Transferases (GSTs ) detoxify mutagenic and genotoxic compounds and therefore control the rate of detoxification of carcinogens. Functional polymorphisms in the genes coding for GSTs alter their enzyme activity in vitro, and were reported to modify EC risk in Asians. We hypothesized that altered enzyme activity GST genotypes influence the susceptibility for esophageal adeno- (EAC) and squamous cell carcinoma (ESCC) in Caucasians.

METHODS

We performed a case-control study including 440 Caucasian patients with EC and 592 healthy Caucasian controls matched for age and sex. Functional polymorphisms were selected and genotypes were determined in GST classes Alpha, Mu, Theta and Pi by means of polymerase chain reaction. Genotypes were classified into predicted high, intermediate and low enzyme activity categories based on in vitro activity data. The distribution of the activity genotypes were compared between patients with EAC or ESCC, and controls. Odds ratios (OR) with 95% confidence intervals (CI) were calculated by logistic regression analyses. Gene-gene interactions were tested and for comparison purposes, the predicted low and intermediate activity genotypes were combined. Genotypes with similar risks for EAC or ESCC were combined and analyzed for multiplicative effects.

RESULTS

Our analyses includes 327 patients with EAC and 106 patients with ESCC. Low or intermediate activity enzyme genotypes for GSTM1, GSTA1, GSTP1 I105V and A114V as well as for GSTT1, did not significantly modify the risk for ESCC or EAC in our Dutch population.

CONCLUSION

Functional genotypes in GST genes are not involved in EAC or ESCC susceptibility in Caucasians, in contrast to results on ESCC from Asia or Africa.

Effects of psychological nursing intervention on personality characteristics and quality of life of patients with esophageal cancer

OBJECTIVE

This study examined the effects of a psychological nursing intervention on personality characteristics and quality of life of esophageal cancer patients.

METHODOLOGY

Esophageal cancer patients (n=86) were randomized into either an intervention group (n=45) or a control group (n=41). Patients in the control group were given routine nursing care, and those in the intervention group were provided with psychological nursing interventions in addition to routine nursing care. Personality characteristics, assessed through Eysenck Personality Questionnaire, and quality of life, assessed through EORTC QLQ-C30, were compared between the two groups.

RESULTS

The results showed that personality characteristics were closely related to quality of life. After the psychological nursing intervention, the main factors were neurosis, psychosis or mood instability, and personality stability. However, introverted and extroverted personality characteristics were not associated with quality of life. The psychological nursing intervention was associated with decreased P-scale and E-scale scores of personality characteristics and improved quality of life in each dimension scored.

CONCLUSIONS

A psychological nursing intervention can affect the personality characteristics of esophageal cancer patients and improve their quality of life; this approach is worthy of further study and clinical application.

Significant association of glutathione S-transferase T1 null genotype with esophageal cancer risk: a meta-analysis

Recent studies on the association between glutathione S-transferase T1 (GSTT1) polymorphism and risk of esophageal cancer showed inconclusive results. To clarify this possible association, we conducted a meta-analysis of published studies. Data were collected from the following electronic databases: Pubmed, Embase, and Chinese Biomedical Database (CBM). The odds ratio (OR) and its 95 % confidence interval (95 % CI) was used to assess the strength of this association. We summarized the data on the association between GSTT1 null genotype and risk of esophageal cancer in the overall population, and performed subgroup analyses by ethnicity. Finally, a total of 24 independent studies including a total of 7,801 subjects (2,965 cases and 4,836 controls) were eligible for meta-analysis. In the overall analysis, there was no significant association between GSTT1 null genotype and esophageal cancer risk (OR = 1.15, 95 % CI 0.99-1.33, P = 0.067). However, meta-analysis of adjusted ORs showed a significant association between GSTT1 null genotype and increased risk of esophageal cancer (OR = 1.30, 95 % CI 1.08-1.56, P = 0.005). Subgroup analyses by ethnicity showed there was an obvious association between GSTT1 null genotype and increased risk of esophageal cancer in East Asians (OR = 1.24, 95 % CI 1.10-1.39, P < 0.001), but not in Caucasians (OR = 0.89, 95 % CI 0.71-1.11, P = 0.300). There was no obvious risk of publication bias in this meta-analysis (Egger's test, P = 0.784). This meta-analysis demonstrates that GSTT1 null genotype is independently associated with increased risk of esophageal cancer, and a race-specific effect may exist in this association.

Cytochrome P450 2E1 RsaI/PstI polymorphism and risk of esophageal cancer: A meta-analysis of 17 case-control studies

The aim of this study was to explore the cytochrome P450 2E1 (CYP2E1) RsaI/PstI polymorphism and risk of esophageal cancer (EC) in mainland Chinese populations. A systematic search of PubMed, EMBASE, Web of Science, CBM, CNKI and VIP databases for publications on the CYP2E1 RsaI/PstI polymorphism and risk of EC was performed. and the genotype data were analyzed in a meta-analysis. Odds ratios (ORs) with relevant 95% confidence intervals (CIs) were estimated to assess the association. Sensitivity analysis, test of heterogeneity and assessment of publication bias were performed. The search yielded 17 studies including 18 trails involving 1,663 cases and 2,603 controls. The meta-analyses showed a significant association between the CYP2E1 RsaI/PstI polymorphism and risk of EC in the mainland Chinese population (c2 vs. c1: OR=0.64; 95% CI, 0.50-0.81; P<0.001; c2/c2 vs. c1/c1: OR=0.73; 95% CI, 0.57-0.93; c2/c2 vs. c1/c1+c1/c2: OR=0.76; 95% CI, 0.60-0.96; P=0.02; c1/c2 vs. c1/c1: OR=0.54; 95% CI, 0.38-0.75; P<0.001; c1/c2+c2/c2 vs. c1/c1: OR=0.48; 95% CI, 0.34-0.70; P<0.001). An increased cancer risk in all genetic models was identified following stratification by ethnicity, source of controls and tumor type. In conclusion, in all genetic models, the association between the CYP2E1 RsaI/PstI polymorphism and risk of EC in the mainland Chinese population was significant. This meta-analysis suggests that the CYP2E1 RsaI/PstI polymorphism is a risk factor for EC, and the c2 allele is a factor that lowers the possibility of EC in the mainland Chinese population and this association did not change due to ethnic differences in genetic backgrounds and the environment.