Genetic variations in esophageal cancer risk and prognosis

Leptin receptor Gln223Arg and Lys109Arg polymorphisms may be associated with HBV-related hepatocellular carcinoma risk: A system review and meta-analysis

Increasing evidence has suggested a strong association of hepatocellular carcinoma (HCC) susceptibility and Gln223Arg (rs1137101) and Lys109Arg (rs1137100) polymorphisms in leptin receptor (LEPR) genes. To provide a quantitative assessment for such correlation, we reviewed all related systems and conducted meta-analysis for case and control researches. A literature search of Web of Science, EMBASE, PubMed, Scopus as well as China National Knowledge Infrastructure databases was collected. 95% confidence intervals (95% CIs) together with odds ratios (ORs) were calculated. Five case-control researches consisting of 1323 cases and 1919 control cases were incorporated into meta-analysis. Researches indicated A-allelic and AA genotype of rs1137101 were substantially related to boosted susceptibility of hepatitis B virus (HBV)-related HCC (mutant model, OR = 1.81, 95% CI = 1.36-2.41, p < .001; allelic model, OR = 1.55, 95% CI = 1.32-1.83, p < .001). On the contrary, we observed GG genotype of rs1137101 substantially related to reduced risk of HBV-related HCC (wild model, OR 0.59, 95%CI = 0.46-0.75, p < .001). We observed AA genotype of rs1137100 relevant to boosted HCC risk (mutant model, OR = 1.51, 95%CI = 1.14-2.01, p = .005) as well as in those with HBV-related HCCs (homozygous model, OR = 2.12, 95%CI = 1.49-3.02, p < .001; mutant model, OR = 1.67, 95%CI = 1.23-2.26, p = .001). G-allele and AA genotype of rs1137101 might be in connection with boosted HBV-related HCC susceptibility, and wild-type GG genotype might prevent diseases. AA genotype of rs1137100 might also improve HBV-related HCC susceptibility. Such conclusions ought to be validated by larger and better-designed researches.

MNS16A polymorphism of the TERT gene on cancer risk: a systematic review and meta-analysis

Some studies have suggested that MNS16A polymorphism in telomerase reverse transcriptase (TERT) gene is associated with cancer risk in various populations and types of cancer. However, the results of previous studies exploring this link have been inconclusive. To be able to accurately assess the association between TERT MNS16A polymorphism and cancer risk, we performed a meta-analysis based on 17 studies described in 12 articles, including 13,764 controls and 7,132 cases. Combined odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were estimated to assess the strength of the association in either a fixed-effects model or, if applicable, a random-effects model. Heterogeneity between articles and their publication bias were also tested. Overall, pooled results showed that no significant association between this polymorphism and cancer was found in the five gene models tested.Considering that there may be too many negative studies in the included studies, diluting the results of the total sample size, we stratified these studies according to ethnicity, source of controls and cancer type. In the stratified analysis, a statistically significant association was observed between Asians and population-based studies. We also analyzed by cancer type and found a significantly increased risk of brain cancer in five genetic models. Our results suggest that TERT MNS16A polymorphism is likely to contribute to increased cancer risk.

Identification of m6a-related signature genes in esophageal squamous cell carcinoma by machine learning method

Background: We aimed to construct and validate the esophageal squamous cell carcinoma (ESCC)-related m6A regulators by means of machine leaning. Methods: We used ESCC RNA-seq data of 66 pairs of ESCC from West China Hospital of Sichuan University and the transcriptome data extracted from The Cancer Genome Atlas (TCGA)-ESCA database to find out the ESCC-related m6A regulators, during which, two machine learning approaches: RF (Random Forest) and SVM (Support Vector Machine) were employed to construct the model of ESCC-related m6A regulators. Calibration curves, clinical decision curves, and clinical impact curves (CIC) were used to evaluate the predictive ability and best-effort ability of the model. Finally, western blot and immunohistochemistry staining were used to assess the expression of prognostic ESCC-related m6A regulators. Results: 2 m6A regulators (YTHDF1 and HNRNPC) were found to be significantly increased in ESCC tissues after screening out through RF machine learning methods from our RNA-seq data and TCGA-ESCA database, respectively, and overlapping the results of the two clusters. A prognostic signature, consisting of YTHDF1 and HNRNPC, was constructed based on our RNA-seq data and validated on TCGA-ESCA database, which can serve as an independent prognostic predictor. Experimental validation including the western and immunohistochemistry staining were further successfully confirmed the results of bioinformatics analysis. Conclusion: We constructed prognostic ESCC-related m6A regulators and validated the model in clinical ESCC cohort as well as in ESCC tissues, which provides reasonable evidence and valuable resources for prognostic stratification and the study of potential targets for ESCC.

The association between depression and esophageal cancer in China: a multicentre population-based study

BACKGROUND

Esophageal cancer (EC) is one of the leading contributors to the global burden of cancer, and the underlying mechanism is still unknown. Recently, there has been a growing interest in understanding modifiable psychosocial risk factors, particularly depression, to prevent EC and reduce morbidity and mortality. However, related research is sparse and has been ignored. The study was designed to assess the association between depression and EC in China.

METHODS

From 2017 to 2019, a population-based multicenter study was conducted in high-risk regions of EC. Participants underwent a free endoscopy screening. If the endoscopic results were suspicious, a pathological biopsy was applied to confirm. Depression was measured with Patient Health Questionnaire-9 (PHQ-9). In addition, information on demographic characteristics and risk factors was collected from participants by trained interviewers using uniform questionnaires.

RESULTS

After Endoscopy and pathologic diagnosis, 15,936 participants in high-risk regions of EC (ECHRRs) were enrolled, 10,907 (68.44%) of which were diagnosed health, 4048 (25.40%) with esophagitis, 769 (4.83%) with low-grade intraepithelial neoplasia (LGIN), 157 (0.99%) with high-grade intraepithelial neoplasia (HGIN), and 55 (0.35%) with EC, respectively. The overall prevalence of depression symptoms of participants was 4.16% (health: 4.63%, esophagitis: 2.99%, LGIN: 2.99%, HGIN: 5.73%, and EC: 9.09%). Multiple logistic regression analyses revealed that the unadjusted OR (95% CI) between depression and each esophageal pathology grades were esophagitis 0.93 (0.92-0.95), LGIN 0.97 (0.94-0.99), HGIN 1.05 (1.00-1.10), and EC 1.04 (0.97-1.14), respectively. However, after adjustment for potential confounders (age, gender, region, alcohol consumption, BMI), no statistically significant associations between depression and EC (adjusted OR = 1.10, 0.99-1.21) and esophageal lesions (esophagitis: adjusted OR = 1.02, 0.99-1.04; LGIN: adjusted OR = 0.98, 0.95-1.01; HGIN: adjusted OR = 1.04, 0.98-1.11) were observed in this study.

CONCLUSIONS

No significant association was observed between depression and EC in the study. Future prospective cohort studies are needed to verify this preliminary finding.

[Prevention of gastrointestinal cancer]

Throughout the past decades, considerable progress has been made in the (early) diagnosis and treatment of gastrointestinal cancers. However, the prognosis for advanced stages of gastrointestinal tumors remains limited for many patients and approximately one third of all tumor patients die as a result of gastrointestinal tumors. The prevention and early detection of gastrointestinal tumors is therefore of great importance.For this reason, we summarize the current state of knowledge and recommendations for the primary, secondary and tertiary prevention of esophageal, stomach, pancreas, liver and colorectal cancer in the following.

Recent advances of m6A methylation modification in esophageal squamous cell carcinoma

In recent years, with the development of RNA sequencing technology and bioinformatics methods, the epigenetic modification of RNA based on N⁶-methyladenosine (m⁶A) has gradually become a research hotspot in the field of bioscience. m⁶A is the most abundant internal modification in eukaryotic messenger RNAs (mRNAs). m⁶A methylation modification can dynamically and reversibly regulate RNA transport, localization, translation and degradation through the interaction of methyltransferase, demethylase and reading protein. m⁶A methylation can regulate the expression of proto-oncogenes and tumor suppressor genes at the epigenetic modification level to affect tumor occurrence and metastasis. The morbidity and mortality of esophageal cancer (EC) are still high worldwide. Esophageal squamous cell carcinoma (ESCC) is the most common tissue subtype of EC. This article reviews the related concepts, biological functions and recent advances of m⁶A methylation in ESCC, and looks forward to the prospect of m⁶A methylation as a new diagnostic biomarker and potential therapeutic target for ESCC.

Genetic variants in m6A modification genes are associated with esophageal squamous-cell carcinoma in the Chinese population

N 6-methyladenosine (m6A) is an abundant modification in RNAs that affects RNA metabolism, and it is reported to be closely related to cancer occurrence and metastasis. In this study, we focused on evaluating the associations between genetic variants in m6A modification genes and the risk of esophageal squamous-cell carcinoma (ESCC). By integrating data of our previous genome-wide association studies and the predictions of several annotation tools, we identified a single nucleotide polymorphism, rs2416282 in the promoter of YTHDC2, that was significantly associated with the susceptibility of ESCC (odds ratio = 0.84, 95% CI: 0.77-0.92, P = 2.81 × 10-4). Through further functional experiments in vitro, we demonstrated that rs2416282 regulated YTHDC2 expression. Knockdown of YTHDC2 substantially promoted the proliferation rate of ESCC cells by affecting several cancer-related signaling pathways. Our results suggested that rs2416282 contributed to ESCC risk by regulating YTHDC2 expression. This study provided us a valuable insight into the roles of genetic variants in m6A modification genes for ESCC susceptibility and may contribute to the prevention of this disease in the future.

Variants in multiple genes are associated with esophageal cancer risk in a Chinese Han population: A case-control study

BACKGROUND

The present study investigated whether 16 single nucleotide polymorphisms (SNPs), selected based on minor allele frequencies, Hardy-Weinberg equilibrium and reported SNPs related to the susceptibility of certain gastrointestinal cancer, were associated with esophageal cancer (EC) risk in a Chinese Han population.

METHODS

We genotyped 16 SNPs among 506 cases and 507 controls using Agena MassARRAY (Agena, San Diego, CA, USA). The association between 16 SNPs and EC risk was analyzed by a chi-squared test and genetic model analysis. Logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

rs1050631 and the rs6214 were associated with a decreased EC risk (OR = 0.75, p = 0.038; OR = 0.74, p = 0.045, respectively). In stratification analysis, the rs9868873 was associated with an increased EC risk (age < 64 years) (OR = 5.03, p = 0.005). The rs6214 was associated with a decreased EC risk (age < 64 years) (OR = 0.59, p = 0.025). The rs861530 was significantly associated with a decreased EC risk (age ≥ 64 years) (OR = 0.67, p = 0.046). rs1050631 was associated with a decreased EC risk in males (OR = 0.71, p = 0.034). In the stratified analysis of clinical stage III/IV, the rs1800566 was associated with a decreased EC risk (OR = 0.49, p = 0.024). Finally, the rs1052133 was associated with an elevated EC risk in the stratified analysis of lymph node metastasis (OR = 1.73, p = 0.025).

CONCLUSIONS

The findings of the present study demonstrate that SLC39A6, IGF1, SEMA5B, XRCC3, NQO1 and OGG1 polymorphisms were associated with EC risk under multiple models.

Genetic variants in GHR and PLCE1 genes are associated with susceptibility to esophageal cancer

Background

Esophageal cancer (EC) is the leading cause of cancer‐related mortality worldwide. The underlying genetic risk factors remain unclear. The association between gene growth hormone receptor (GHR) and phospholipase C epsilon 1 (PLCE1) polymorphisms and the EC risk were identified in this study.

Methods

A total of 506 EC cases and 507 controls were included in this research. Two SNPs (rs6898743 of GHR and rs2274223 of PLCE1) were selected and genotyped. The associations between gene polymorphisms and the EC risk were assessed by logistic regression analysis. The databases RegulomeDB, GTEx, and UALCAN were used for functional annotations.

Results

In the allelic frequencies analysis, the rs6898743 of GHR was associated with decreased susceptibility of EC (OR = 0.83, 95% CI: 0.70–1.00, p = 0.049), while rs2274223 of PLCE1 was associated with increased 0.25‐fold EC risk (OR = 1.25, 95% CI: 1.02–1.53, p = 0.037). The “GC” genotype of rs6898743 was associated with a 0.24‐fold decreased risk of EC under co‐dominant model (OR = 0.76, 95% CI: 0.58–0.99, p = 0.046), and the “GA” genotype of rs2274223 was associated with increased EC risk under co‐dominant model (OR = 1.36, 95% CI: 1.04–1.77, p = 0.023). Using GTEx database, rs2274223 was found to be significant associated with increased PLCE1 expression (p = 4.1 × 10⁻⁷) in esophagus muscularis. The UALCAN database demonstrated that the GHR gene was under‐expressed in esophageal cancer tissues (p = 0.017).

Conclusion

The gene GHR and PLCE1 polymorphisms are associated with EC in the general population and the results need to be verified in future.

A functional variant in TNXB promoter associates with the risk of esophageal squamous-cell carcinoma

Our previous study identified a tag single-nucleotide polymorphism (SNP) rs204900 in TNXB associated with risk of esophageal squamous-cell carcinoma (ESCC) in the Chinese population. However, the functional role of TNXB and causal variants had not been interrogated in that study. In the present study, we explored the effects of TNXB expression in the development of ESCC and searched for functional variants in this gene. We found TNXB was downregulated in ESCC tumors. Using small interfering RNAs and CRISPR-Cas9 methods, we identified that both knockdown and knockout of TNXB significantly promoted ESCC cell growth in vitro, suggesting a tumor suppressor role of this gene in ESCC. Through further fine-mapping analysis, we identified that a noncoding variant in the promoter of TNXB, rs411337, predisposed to ESCC risk (odds ratio = 1.36, 95% confidence interval: 1.22-1.51, P = 9.10 × 10^-9 ). These findings revealed the functional mechanism of TNXB in the development of ESCC and may contribute to the prevention and treatment of this disease in the future.

Esophageal cancer genetics in South Africa

Esophageal cancer (EC) is an extremely aggressive cancer with one of the highest mortality rates. The cancer is generally only diagnosed at the later stages and has a poor 5-year survival rate due to the limited treatment options. China and South Africa are two countries with a very high prevalence rate of EC. EC rates in South Africa have been on the increase, and esophageal squamous cell carcinoma is the predominant subtype and a primary cause of cancer-related deaths in the black and male mixed ancestry populations in South Africa. The incidence of EC is highest in the Eastern Cape Province, especially in the rural areas such as the Transkei, where the consumption of foods contaminated with Fusarium verticillioides is thought to play a major contributing role to the incidence of EC. China is responsible for almost half of all new cases of EC globally. In China, the prevalence of EC varies greatly. However, the two main areas of high prevalence are the southern Taihang Mountain area (Linxian, Henan Province) and the north Jiangsu area. In both countries, environmental toxins play a major role in increasing the chance that an individual will develop EC. These associative factors include tobacco use, alcohol consumption, nutritional deficiencies and exposure to environmental toxins. However, genetic polymorphisms also play a role in predisposing individuals to EC. These include single-nucleotide polymorphisms that can be found in both protein-coding genes and in non-coding sequences such as miRNAs. The aim of this review is to summarize the contribution of genetic polymorphisms to EC in South Africa and to compare and contrast this to the genetic polymorphisms observed in EC in the most comprehensively studied population group, the Chinese.

PLCE1 Polymorphisms and Risk of Esophageal and Gastric Cancer in a Northwestern Chinese Population

The reported risk susceptibility between phospholipase C epsilon 1 (PLCE1) polymorphisms and esophageal cancer (EC) and gastric cancer (GC) remained inconsistent and controversial, especially on variants other than rs2274223. The relationship between PLCE1 polymorphisms and gene expression is also unclear. Here we conducted a case-control study from northwest China, genotyped seven tag single nucleotide polymorphisms (SNPs) in PLCE1 with multiplexed SNP MassARRAY assay. Stratified analysis was carried out and PLCE1 expression was evaluated in specified groups with the method of qRT-PCR and immunohistochemistry. Results showed that the minor alleles of rs3765524, rs2274223, and rs10509670 were associated with increased risk of EC and GC. Linkage disequilibrium analysis revealed protective haplotypes of CCAAGTC and CCAA. By stratification, a more significant association was found in subgroups of male, age ≥ 54, tumor stages of I-II and tumor size ≤ 5 cm, EC and cardia cancer (CC) of stomach, and moderate to well differentiated squamous carcinoma. In addition, a significant association for rs3765524 with noncardia cancer (NCC) and adenocarcinoma which is predominant in China was also observed. Further expression analysis identified that PLCE1 was downregulated in NCC tissues comparing to their adjacent noncancerous tissues, and its protein expression was higher in genotype rs3765524 CT/TT than in rs3765524 CC. In summary, our study suggests that PLCE1 polymorphisms may affect its gene expression and are associated with not only EC and CC, but also, to some extent, NCC risk in this study population.

Genetic variants at 9p21.3 are associated with risk of esophageal squamous cell carcinoma in a Chinese population

Genome‐wide association studies have linked genetic variants at 9p21.3 to the risk of multiple cancers. However, the roles of genetic variants at 9p21.3 in esophageal squamous cell carcinoma (ESCC) development are largely unknown. We evaluated the genetic variants at 9p21.3 reported in cancer genome‐wide association studies with a case–control study including 2139 ESCC cases and 2273 controls in a Chinese population, and measured the mRNA expression levels of MTAP,CDKN2A,CDKN2B, and CDKN2B‐AS1 in paired ESCC tumor and adjacent normal tissues. We found that the G allele of rs7023329 was significantly associated with a decreased risk of ESCC with a per‐allele odds ratio of 0.84 (95% confidence interval, 0.77–0.91; P = 2.95 × 10⁻⁵). The rs7023329‐G allele was related to a high expression of MTAP (P = 0.020). The rs1679013‐C allele was independently associated with an increased risk of ESCC with a per‐allele odds ratio of 1.12 (95% confidence interval, 1.01–1.24; P = 0.039). We also found that the carriers of the risk allele rs1679013‐C had lower expression of CDKN2B than non‐carriers (P = 0.035). CDKN2B was also significantly downregulated in ESCC tumor tissues compared with adjacent normal tissues (P = 3.50×10⁻⁵). Therefore, our findings indicate that genetic variants at 9p21.3 may modulate the expression of MTAP and CDKN2B and contribute to ESCC susceptibility. This may further advance our understanding of the 9p21.3 locus in cancer development.

Resveratrol mediates cell cycle arrest and cell death in human esophageal squamous cell carcinoma by directly targeting the EGFR signaling pathway

Resveratrol is a small polyphenol that has been intensively studied in a wide spectrum of therapeutic fields. More recently, resveratrol has been demonstrated to exert its antitumor activity in numerous tumor models. The present study reported that resveratrol exhibited a marked anti-proliferative effect on human esophageal squamous cell carcinoma (ESCC) cells by inducing cell cycle G₀/G₁ phase arrest and cell death, which was associated with a decrease in the expression levels of cyclin D1 and an increase in cleaved PARP/cleaved caspase-3 expression levels. The mechanisms underlying the antitumor potency of resveratrol were principally attributed to the downregulation of epidermal growth factor receptor (EGFR) signaling. The western blotting results showed that exposure of ESCC cells to resveratrol inhibited EGF-induced EGFR activation in addition to decreasing the total protein levels of EGFR and membrane/nuclear localization. In summary, the results suggested that resveratrol, or an associated analog, may have a role in the management of human ESCC.

Differences in esophageal cancer characteristics and survival between Chinese and Caucasian patients in the SEER database

Background

To compare the clinicopathologic characteristics and survival of Chinese and Caucasian esophageal cancer (EC) patients residing in the US, using a population-based national registry (Surveillance Epidemiology and End Results [SEER]) database.

Methods

Patients with EC were identified from the SEER program from 1988 to 2012. Kaplan–Meier survival methods and Cox proportional hazards regression were performed.

Results

A total of 479 Chinese and 35,748 Caucasian EC patients were identified. Compared with Caucasian patients, the Chinese patients had a later year of diagnosis, remained married after EC was diagnosed, had esophageal squamous cell carcinomas (ESCCs) more frequently, had tumors located in the upper-third and middle-third of the esophagus more frequently, and fewer patients presented with poorly/undifferentiated EC and underwent cancer-directed surgery. In Chinese patients, the incidence of esophageal adenocarcinomas (EACs) increased from 1988 to 2012 (P=0.054), and the majority of EAC patients had tumors located in the lower thoracic esophagus. The overall survival (OS) was not significantly different between Chinese and Caucasian patients (P=0.767). However, Chinese patients with ESCC had a significantly better OS when compared to their Caucasian counterparts, whereas there was no significant difference in the OS between Chinese and Caucasian patients with EAC.

Conclusion

The presenting demographic features, tumor characteristics, and outcomes of EC patients differed between Chinese and Caucasian patients residing in the US. Chinese patients diagnosed with EAC tended to share similar clinical features with their Caucasian counterparts, and the Chinese patients with ESCC had better OS than their Caucasian counterparts.

Decreased risk of developing cancer in subjects carrying SLC52A3 rs13042395 polymorphism: proof from a meta-analysis

AIM

This study aimed to conduct a meta-analysis to explore the association between SLC52A3 rs13042395 polymorphism and cancer risk.

MATERIALS & METHODS

A comprehensive literature search was performed to confirm the relationship evaluated using STATA 12.0 software.

RESULTS

Overall, SLC52A3 rs13042395 C>T polymorphism was associated with cancer risk in two genetic models (TT vs CC: odds ratio: 0.86; 95% CI: 0.80-0.93; p < 0.001, TT vs CC + CT: odds ratio: 0.88; 95% CI: 0.82-0.95; p = 0.001). Significant associations were found between SLC52A3 rs13042395 polymorphism and decreased cancer risk among esophageal cancer, Asians, female, normal BMI and old age groups. No significant associations were observed in alcohol and smoking groups.

CONCLUSION

SLC52A3 rs13042395 C>T polymorphism might be a potential biomarker for cancer susceptibility.

Association between alcohol dehydrogenase-2 gene polymorphism and esophageal cancer risk: a meta-analysis

BACKGROUND

It has been shown that gene polymorphisms may play an important role in the carcinogenesis of esophageal cancer. This study is to investigate the role of alcohol dehydrogenase 1B (ADH1B) gene Arg47His polymorphism in esophageal cancer susceptibility.

METHODS

Case-control studies published between January 2000 and June 2015 were searched to retrieve relevant articles. The pooled odds ratio (OR) and 95 % confidence interval (CI) were employed to calculate the strength of association.

RESULTS

A total of 23 relevant articles were finally selected for the analysis, including 9338 esophageal cancer patients and 14,896 matched controls. Overall, we found that the 47His allele was significant associated with the decreased risk of esophageal cancer when compared with the 47Arg allele in total populations (A vs. G: OR = 0.67, 95 % CI = 0.59-0.76, P < 0.00001). This protective relationship was observed under other genetic models as well (P < 0.00001). Subgroup analysis by ethnicity showed that ADH1B Arg47His variant was associated with the decreased esophageal cancer risk under all the genetic models (P < 0.00001) among Asians, especially in Chinese and Japanese; while in non-Asians, no significant correlation was detected in any genetic models (P > 0.05). Furthermore, Arg/Arg genotype of ADH1B Arg47His variant combined with drinking, smoking and males appeared to show a high risk in patients with esophageal cancer.

CONCLUSIONS

Our results suggested that ADH1B gene Arg47His variant was associated with the decreased esophageal cancer risk. Genetic-environmental interaction should be further considered in the future researches.

Regulatory Role of miR-203 in Occurrence and Progression of Kazakh Esophageal squamous cell carcinoma

Esophageal carcinoma is one of the most common malignant tumors and the Kazakh national minority (ethnic) in Xinjiang (northwest of China) has been reported to be one of the highest incidence of Esophageal squamous cell carcinoma (ESCC) in the world. MicroRNA-203 (miR-203) was described as a tumor-suppressive miRNA in several cancers, but little study about the role of miR-203 in Kazakh ESCC. Therefore, we aimed to investigate the role of miR-203 in the occurrence and progression of Kazakh ESCC. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect miR-203 expression, and immunohistochemistry (IHC) was used to examine P63 expression. The expression level of miR-203 in ESCC was significantly lower than that of cancer adjacent normal (CAN) samples (P < 0.05). Whereas the expression level of P63 in ESCC was significantly higher than that of CAN samples (P < 0.05), an inverse association between the expression of P63 and miR-203 was found but was not statistically significant (P > 0.05). These findings suggest that miR-203 is a tumor suppressor gene that plays an important role in inhibiting the occurrence of Kazakh ESCC in Xinjiang, China.

Polymorphisms in the 5' upstream regulatory region of p21(WAF1/CIP1) and susceptibility to oesophageal squamous cell carcinoma

This study aims to scan the 5'-upstream regulatory region of the p21 gene to identify all putative functional single nucleotide polymorphisms (SNPs) and to evaluate the contribution of p21 variants to oesophageal squamous cell carcinoma (ESCC) in the Chinese Han population. Common SNPs were identified, and both locus-based and haplotype-based association tests were used to evaluate the potential risk of these p21 gene polymorphisms for ESCC. Immunohistochemistry assay was further performed to detect the P21 protein expression in ESCC specimens. Twenty three SNPs were identified and seven Tagging SNPs were chosen to represent all 23 SNPs. Univariate analysis indicated that the rs3829963 C and the rs2395655 G alleles increased susceptibility to ESCC (OR = 1.606 and OR = 1.572, respectively). The rs3829963 C and rs2395655 G alleles, combined with cigarette smoking, could further increase the risk for ESCC (OR = 2.657 and OR = 2.828, respectively). Additionally, the rs2395655 G allele appeared to elevate the positive rate of P21 expression in ESCC tissues, as compared to the A allele. This report demonstrates for the first time that rs3829963 and rs2395655, in the promoter of the p21 gene are potentially functional, modulating susceptibility to ESCC among the high-risk cigarette-smoking Chinese population.

HLA-DRB1 and HLA-DQB1 methylation changes promote the occurrence and progression of Kazakh ESCC

Human leukocyte antigen II (HLA-II) plays an important role in host immune responses to cancer cells. Changes in gene methylation may result in aberrant expression of HLA-II, serving a key role in the pathogenesis of Kazakh esophageal squamous cell carcinoma (ESCC). We analyzed the expression level of HLA-II (HLA-DP, -DQ, and -DR) by immunohistochemistry, as well as the methylation status of HLA-DRB1 and HLA-DQB1 by MassARRAY spectrometry in Xinjiang Kazakh ESCC. Expression of HLA-II in ESCC was significantly higher than that in cancer adjacent normal (ACN) samples (P < 0.05). Decreased HLA-II expression was closely associated with later clinical stages of ESCC (P < 0.05). Hypomethylation of HLA-DRB1 and hypermethylation of HLA-DQB1 was significantly correlated with occurrence of Kazakh ESCC (P < 0.01), and mainly manifested as hypomethylation of CpG9, CpG10-11, and CpG16 in HLA-DRB1 and hypermethylation of CpG6-7 and CpG16-17 in HLA-DQB1 (P < 0.01). Moreover, hypomethylation of HLA-DQB1 CpG6-7 correlated with poor differentiation in ESCCs, whereas hypermethylation of HLA-DRB1 CpG16 and hypomethylation of HLA-DQB1 CpG16-17 were significantly associated with later stages of ESCC (P < 0.05). A significant inverse association between HLA-DRB1 CpG9 methylation and HLA-II expression was found in ESCC (P < 0.05). These findings suggest aberrant HLA-DRB1 and HLA-DQB1 methylation contributes to the aberrant expression of HLA-II. These molecular changes may influence the immune response to specific tumor epitopes, promoting the occurrence and progression of Kazakh ESCC.

Lack of association between LEPR Lys656Asn or Ser343Ser polymorphisms and cancer susceptibility: A meta-analysis

Previous studies have shown conflicting results between the association of leptin receptor (LEPR) genetic polymorphisms and cancer risk. The frequent LEPR Lys656Asn or Ser343Ser genetic polymorphism has been demonstrated to be functional and may promote genetic susceptibility to cancers. However, the association between the LEPR Lys656Asn or Ser343Ser genetic polymorphism and cancer risk remains to be determined. To improve the understanding of the LEPR Lys656Asn or Ser343Ser genetic polymorphism role in global cancer, a comprehensive meta-analysis was conducted that comprised 2,480 cases and 3,162 controls. The LEPR Lys656Asn or Ser343Ser genetic polymorphism did not significantly affect the cancer risk. In the stratified analysis, there was no significant association of the LEPR Lys656Asn or Ser343Ser variants with any type of cancer under any model. In addition, significantly increased risks were found in the Asian population in heterozygous codominant [odds ratio (OR), 1.24 (1.01-1.53)] and dominant [OR, 1.24 (1.02-1.50)] genetic models. A significantly increased susceptibility to cancer was not found when stratified by study design. There were no significant differences found in genotype method and sample size in cases among the genotypes. These findings indicated a lack of association between LEPR Lys656Asn or Ser343Ser polymorphisms and cancer susceptibility, however, these polymorphisms may increase the cancer susceptibility among the Asian population, particularly in the dominant genetic model. The single-nucleotide polymorphism is also suggested to function as a dominant mutation, which requires verification or association with functional studies.

Upregulation of STK15 in esophageal squamous cell carcinomas in a Mongolian population

BACKGROUND

The STK15 gene located on chromosome 20q13.2 encodes a centrosome-associated kinase critical for regulated chromosome segregation and cytokinesis. Recent studies have demonstrated STK15 to be significantly associated with many tumors, with aberrant expression obseved in many human malignancies. The purpose of this study was to investigate expression of STK15 in esophageal squamous cell carcinomas (ESCCs) in a Mongolian population.

METHODS

Two non-synonymous single nucleotide polymorphisms in the coding region of STK15, rs2273535 (Phe31Ile) and rs1047972 (Val57Ile) were assessed in 380 ESCC patients and 380 healthy controls. We also detected STK15 mRNA expression in 39 esophageal squamous cell carcinomas and corresponding adjacent tissues by real time PCR.

RESULTS

rs2273535 showed a significant association with ESCC in our Mongolian population (rs227353, P allele=0.0447, OR (95%CI)=1.259 (1.005~1.578)). Real time PCR analysis of ESCC tissues showed that expression of STK15 mRNA in cancer tissues was higher than in normal tissues (p=0.013).

CONCLUSIONS

Our study showed that functional SNPs in the STK15 gene are associated with ESCC in a Mongolian population and up-regulation of STK15 mRNAoccurs in ESCC tumors compared adjacent normal tissues. STK15 may thus have an important role in the prognosis of ESCC and be a potential therapeutic target.

Cytochrome P450 1A1 (CYP1A1) polymorphism and susceptibility to esophageal cancer: an updated meta-analysis of 27 studies

Cytochrome P450 1A1 (CYP1A1) polymorphisms are known to play a crucial role in the development and metastasis of malignant diseases including esophageal cancer. However, the results of previous studies investigating the association between CYP1A1 polymorphisms and esophageal cancer risk have been inconsistent. This meta-analysis of 27 eligible studies, encompassing 4,215 esophageal cancer cases and 6,339 control subjects, pooled the odds ratios (ORs) with corresponding 95 % confidence intervals (95 % CI) to assess this association. The effects of ethnicity (Caucasian and Asian) and histopathology type (esophageal squamous cell carcinoma and esophageal adenocarcinoma) were considered in subgroup analyses. A significant association was observed between the CYP1A1 Ile/Val gene polymorphism and esophageal cancer in all of the genetic models (Ile/Val vs. Ile/Ile, OR = 1.41, 95 % CI = 1.25-1.58; Val/Val vs. Ile/Ile, OR = 1.94, 95 % CI = 1.34-2.82; Ile/Val + Val/Val vs. Ile/Ile, OR = 1.49, 95 % CI = 1.33-1.66). The subgroup analysis based on ethnicity showed that the association between the CYP1A1 Ile/Val polymorphism and esophageal cancer existed in Asian and Caucasian populations. However, no association was observed between the CYP1A1 MspI polymorphism and esophageal cancer in either subgroup or in the overall population. These results suggested that the CYP1A1 Ile/Val polymorphism was associated with an increased risk of esophageal cancer, whereas the CYP1A1 MspI polymorphism may not have increased susceptibility to esophageal cancer. Further studies are required to confirm these findings.

Association of LEP A19G polymorphism with cancer risk: a systematic review and pooled analysis

The results from the published studies on the association between leptin (LEP) genetic polymorphism and cancer risk are conflicting. The common A19G (rs2167270) genetic polymorphism has been reported to be functional and may contribute to genetic susceptibility to cancers. However, the association between LEP A19G (rs2167270) genetic polymorphism and cancer risk remains inconclusive. To better understand the role of LEP A19G (rs2167270) genetic polymorphism in global cancer, we conducted this comprehensive meta-analysis encompassing 5,679 cases and 7,443 controls. Overall, the LEP A19G (rs2167270) genetic polymorphism was associated with lower cancer risk. In the stratified analysis, significant associations were found between the LEP A19G (rs2167270) genetic polymorphism and colorectal cancer and non-Hodgkin's lymphoma. For colorectal cancer, there was no significant association of LEP A19G (rs2167270) variant with this disease under heterozygous codominant model [odds ratio (OR) = 1.11 (0.97-1.27)], dominant genetic model [OR = 1.03 (0.91-1.17)], and additive genetic model [OR = 0.94 (0.86-1.03)]; however, there was a marginal association under homozygous codominant model [OR = 0.80 (0.66-0.97)] and recessive genetic model [OR = 0.75 (0.63-0.90)]. For non-Hodgkin's lymphoma, there was a significant association of LEP A19G (rs2167270) variant with the disease under homozygous codominant model [OR = 0.74 (0.59-0.94)], recessive genetic model [OR = 0.76 (0.61-0.94)], and additive genetic model [OR = 0.89 (0.80-0.99)], but not under heterozygous codominant model [OR = 0.95 (0.82-1.10)] and dominant genetic model [OR = 0.91 (0.79-1.04)]. Moreover, a significantly decreased cancer risk was found in recessive genetic model among Latin American population. When stratified by study design, significantly elevated susceptibility to cancer was not found among any studies. No significantly differences in genotype method and sample size in cases were found among genotypes. These findings suggest that the LEP A19G (rs2167270) genetic polymorphism may decrease the susceptibility to cancers in colorectal cancer and non-Hodgkin's lymphoma, when assuming a homozygote codominant model and a recessive genetic model among Latin American population. The phenomenon also indicates that the SNP functions as a recessive mutation, which needs to be verified or linked with functional studies.

Inactivation of miR-34a by aberrant CpG methylation in Kazakh patients with esophageal carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is an aggressive tumor with dismal prognosis and high incidence and mortality in Kazakh population. MiR-34a, a direct p53 target gene, possesses tumor-suppressive properties as they mediate apoptosis, cell cycle arrest, and senescence. The reduced expression of miR-34a by methylation in various cancers has been reported.

Methods

To determine whether aberrant miR-34a methylation occurs in esophageal cancer, the DNA methylation of 23 CpGs sites in the miR-34a promoter was quantitatively analyzed in relation to the translation initiation site by MALDI -TOF mass spectrometry in 59 ESCC tissues and 34 normal tissues from the Kazakh population. Real-time PCR was used to detect the inhibition of miR-34a expression levels and to evaluate their association with methylation.

Results

We found that miR-34a is more frequently methylated in ESCC (0.133 ± 0.040) than in controls (0.066 ± 0.045, P < 0.01). A nearly two-fold increase in miR-34a expression for the hypomethylated promoter was found in normal esophageal tissues than ESCC with hypermethylation (P <0.0001), pointing to a negative relationship between miR-34a CpG sites methylation and expression(r = −0.594, P = 0.042). The hypermethylation of miR-34a CpG_8.9 was associated with the advanced UICC stage III/IV of the esophageal cancers, and the hypermethylation of CpG_8.9 and CpG_5 of miR-34a was significantly correlated with lymph node metastasis.

Conclusions

Our findings suggest that miR-34a is involved in the etiology of ESCC and that hypermethylated miR-34a is a potential biomarker for ESCC diagnosis and prognosis. Moreover, targeting miR-34a methylation by demethylating agents may offer a novel strategy for anticancer therapy of ESCC.

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.

Multiple polymorphisms within the PLCE1 are associated with esophageal cancer via promoting the gene expression in a Chinese Kazakh population

Although recent genome-wide association studies of esophageal squamous cell carcinoma (ESCC) identified a susceptibility locus in phospholipase C epsilon 1 (PLCE1) in Chinese Han populations, few studies further confirmed these findings in pure Kazakh population in which there are higher incidence and mortality of ESCC. Here, we investigated the potential associations between 19 SNPs of PLCE1 and susceptibility to ESCC in 222 cases and 326 controls from a pure ethnic population of Kazakh. Real-time PCR and immunohistochemistry were performed to detect the PLCE1 expression levels and evaluate their association with PLCE1 polymorphism. We found that only 4 SNPs (rs753724, rs11187842, rs2274223, and rs12263737) with moderate linkage disequilibrium (LD) confer significantly increased risk of ESCC, with the ORs ranging from 1.43 to 2.04, and there was a risk allele dose-dependent increase in ESCC risk (P-trend=0.043). Especially, the risk effects of rs2274223 were more evident in poor differentiation and advanced clinical stages of Kazakh ESCC. Additionally, the significantly lowest PLCE1 mRNA expression was found in the KYSE-150 cell line having no risk alleles compared with other three cell lines having risk alleles, and the normal tissues of both homozygous mutant type of PLCE1 rs12263737 and rs2274223 had a higher PLCE1 staining score than that of homozygous wild type. Our findings suggested that genetic variants in PLCE1 might serve as candidate markers for Kazakh ESCC susceptibility, and these LD variants might influence ESCC risk individually and jointly by promoting the messenger RNA and protein expression of the gene.

Recent developments in esophageal adenocarcinoma

Answer questions and earn CME/CNE Esophageal adenocarcinoma (EAC) is characterized by 6 striking features: increasing incidence, male predominance, lack of preventive measures, opportunities for early detection, demanding surgical therapy and care, and poor prognosis. Reasons for its rapidly increasing incidence include the rising prevalence of gastroesophageal reflux and obesity, combined with the decreasing prevalence of Helicobacter pylori infection. The strong male predominance remains unexplained, but hormonal influence might play an important role. Future prevention might include the treatment of reflux or obesity or chemoprevention with nonsteroidal antiinflammatory drugs or statins, but no evidence-based preventive measures are currently available. Likely future developments include endoscopic screening of better defined high-risk groups for EAC. Individuals with Barrett esophagus might benefit from surveillance, at least those with dysplasia, but screening and surveillance strategies need careful evaluation to be feasible and cost-effective. The surgery for EAC is more extensive than virtually any other standard procedure, and postoperative survival, health-related quality of life, and nutrition need to be improved (eg, by improved treatment, better decision-making, and more individually tailored follow-up). Promising clinical developments include increased survival after preoperative chemoradiotherapy, the potentially reduced impact on health-related quality of life after minimally invasive surgery, and the new endoscopic therapies for dysplastic Barrett esophagus or early EAC. The overall survival rates are improving slightly, but poor prognosis remains a challenge.

High expression of lysine-specific demethylase 1 correlates with poor prognosis of patients with esophageal squamous cell carcinoma

Recent studies have elucidated the role of lysine-specific demethylase 1 (LSD1), a member of the histone demethylases, in epigenetic regulation of tumor suppressing/promoting genes and neoplastic growth. However, the expression of LSD1 in patients with esophageal squamous cell carcinoma (ESCC) is still unknown. Here, we reported that LSD1 expression was elevated in cancerous tissue and correlated with lymph node metastasis and poorer overall survival in patients with ESCC. Compared to EC109 cells, LSD1 expression was unregulated in aggressive cancer cell lines KYSE450 and KYSE150. Knockdown of LSD1 using lentivirus delivery of LSD1-specific shRNA abrogated the migration and invasion of ESCC cells in vitro. Further, a LSD1 inhibitor, tranylcypromine, suppressed H3K4me2 demethylation and attenuated cellular motility and invasiveness in a dose-dependent manner. Taken together, these data suggested that LSD1 was a potential prognostic maker and may be a molecular target for inhibiting invasion and metastasis in ESCC.

Overexpression of PLCE1 in Kazakh esophageal squamous cell carcinoma: implications in cancer metastasis and aggressiveness

Three recent large-scale genome-wide association studies (GWAS) in Chinese Han populations have identified an esophageal squamous cell carcinoma (ESCC) susceptibility locus within phospholipase C epsilon 1 (PLCE1) gene, which encodes a phospholipase involved in intracellular signaling. The expressed PLCE1 in ESCC, however, are inconsistent. This study examined PLCE1 expression by immunohistochemistry (IHC) from 110 ethnic Kazakh ESCC patients and 50 from adjacent normal esophageal tissues (NETs). The expressed PLCE1 was localized in cytoplasm, especially in the peripheral layers of cancer cell nests, which was significantly higher in tumors than in NETs (p < 0.001). Increased expression of PLCE1 was correlated with advanced tumor-node-metastasis (TNM) stages (p = 0.015) and lymph node metastasis (p = 0.003) in patients with ESCC. Of the 110 patients, we examined 50 paired ESCC tissues and corresponding NETs by quantitative RT-PCR (polymerase chain reaction) and the mean mRNA level of PLCE1 in ESCC was 1.85-fold higher compared with those in corresponding NETs (p = 0.0012). Meanwhile, 4 of 5 ESCC cell lines also showed elevated expression of PLCE1 mRNA. Furthermore, elevated expression of PLCE1 mRNA in Kazakh ESCC was associated with its immunoreactivity (ρ = 0.297, p = 0.040), lymph node metastasis (p < 0.001), and advanced TNM stages of ESCC (p = 0.013). To our knowledge, this study demonstrates for the first time that PLCE1 overexpression correlates with lymph node metastasis and advanced TNM stages of Kazakh ESCC, implicating a role of PLCE1 in cancer metastasis and aggressiveness in ethnic Kazakh patients with ESCC. Furthermore, the current findings may warrant investigations into whether inhibiting PLCE1 could be a strategy for targeted anticancer therapy particularly for Kazakh ESCC.

The hMLH1 promoter polymorphisms and cancer susceptibility in Asian populations: a meta-analysis

BACKGROUND

A variety of studies have evaluated the associations between polymorphisms in the promoter regions of the hMLH1 and cancer risk. However, the results remain inconclusive. To better understand the roles of the hMLH1 polymorphisms and cancer risk, we conducted a comprehensive meta-analysis to investigate the association between the hMLH1 -93G/A and 1151T/A (Val384Asp) polymorphisms and cancer risk in Asian population.

METHODS

We performed a meta-analysis by conducting searches of the published studies in Pub Med, CNKI, CBM, ISI web of knowledge and Google scholar search databases. Finally, 12 studies were included into our meta-analysis. Overall and subgroup analyses were performed. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the associations between hMLH1 polymorphisms and cancer risk. Statistical analysis was performed with Review Manager 5.0.

RESULTS

Twelve studies addressing two hMLH1 polymorphisms were analyzed among a total of 4128 cancer cases and 4678 controls. For hMLH1 -93G/A, there was no evidence that the hMLH1 -93G/A polymorphism was significantly associated with an increased cancer risk (P>0.05) in Asian populations (heterozygote comparison: OR=0.89 [95% CI (0.75, 1.060)] P=0.20; dominant model comparison: OR=0.98 [95% CI (0.83, 1.15)] P=0.79). In subgroup analysis based on cancer types and the sources of control, no associations were found in colorectal cancer, gastric cancer and "other cancers" under the any gene model except for lung cancer (recessive model comparison: OR=1.69 [95% CI (1.30, 2.19)] P<0.0001). For hMLH1 1151T/A, the polymorphism significantly associated with an increased cancer risk in Asians: OR=1.88 [95% CI (1.49, 2.25)], P<0.0001, and OR=1.87 [95% CI (1.49, 2.25)], P<0.0001.

CONCLUSIONS

Our investigations demonstrated that the hMLH1 -93G/A polymorphism is not a candidate for susceptibility to overall cancers, and that the hMLH1 1151T/A polymorphism is significantly associated with higher cancer risk in Asian populations. Further studies with large sample size for hMLH1 should be conducted.

1790 G/A polymorphism, but not 1772 C/T polymorphism, is significantly associated with cancers: an update study

This study aimed to investigate the association between PASD8 gene and cancers. For 1772 C/T polymorphism (rs11549465), it included 5552 cases and 8044 controls, and for 1790 G/A (rs11549467), 3381 cases and 5830 controls. The allele-analysis results showed that 1772 C/T (rs11549465) was significantly associated with cancers (OR: 1.177, 95% CI: 1.011-1.369, p=0.035). And results of genotype-analysis indicated that 1790 G/A (rs11549467) had a significant relationship with cancers. (OR: 0.736, 95% CI: 0.595-0.910, p=0.005). For 1790 G/A (rs11549467), the association was significant when subdivided by different kinds of cancers. And no association existed when subdivided into population-type subgroups. In conclusion, PASD8 gene played an important role in the development of cancers.

Association of SMAD7 rs12953717 polymorphism with cancer: a meta-analysis

BACKGROUND

Accumulating evidence has suggested that Mothers against decapentaplegic homolog 7 (SMAD7) rs12953717 polymorphism might be related to cancer risk. However, epidemiologic findings have been inconsistent. We therefore performed a meta-analysis to clarify the association between the SMAD7 rs12953717 polymorphism and cancer risk.

METHODS

A comprehensive search was conducted to identify all eligible studies of SMAD7 rs12953717 polymorphism and cancer risk. We used odds ratios (ORs) to assess the strength of the association, and 95% confidence intervals (CIs) to give a sense of the precision of the estimate. Heterogeneity, publication bias, and sensitivity analysis were also explored.

RESULTS

A total of 14 case-control studies, including 16928 cases and 14781 controls, were included in the present meta-analysis. The overall results showed that the variant genotypes were associated with a significantly increased risk of all cancer types (homozygote comparison, OR = 1.23, 95%CI = 1.10-1.38, P<0.01; heterozygote comparison, OR = 1.12, 95%CI = 1.02-1.22, P = 0.02; recessive model, OR = 1.17, 95%CI = 1.07-1.29, P<0.01; dominant model, OR = 1.15, 95%CI = 1.06-1.25, P<0.01; allelic model, OR = 1.12, 95%CI = 1.06-1.18, P<0.01). Further sensitivity analysis confirmed the significant association. In the subgroup analysis by ethnicity, SMAD7 rs12953717 polymorphism was significantly associated with cancer risk in both Caucasians and Asians. In the subgroup analysis by cancer types, SMAD7 rs12953717 polymorphism was significantly associated with colorectal cancer.

CONCLUSIONS

Our investigations demonstrate that rs12953717 polymorphism is associated with the susceptibility of cancer. Large-scale and well-designed case-control studies are necessary to validate the risk identified in the present meta-analysis.

The TERT MNS16A polymorphism contributes to cancer susceptibility: meta-analysis of the current studies

The MNS16A polymorphism in the telomerase reverse transcriptase (TERT) gene has been implicated in cancer risk in multiple populations and various types of cancers; however, the results of previous studies exploring this association were inconclusive. To more precisely evaluate the relationship between the TERT MNS16A polymorphism and cancer risk, we performed a meta-analysis based on 8 studies described in 7 articles comprising 7864 controls and 4355 cases. The summary odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were estimated to assess the strength of the association in a fixed-effects model or a random-effects model where appropriate. Heterogeneity among articles and their publication bias were also tested. Overall, the pooled results indicated that the MNS16A polymorphism was significantly associated with increased cancer risk in the homozygote comparison model (SS vs. LL: OR=1.280, 95% CI 1.060-1.547) and the recessive model (SS vs. LL+SL: OR=1.201, 95% CI 1.004-1.436). In the stratified analyses, a statistically significant association was observed among Caucasians and in population-based studies. We also performed the analyses by cancer type, and a significantly increased risk of glioma was found in four genetic models. Our results suggest that the TERT MNS16A polymorphism most likely contributes to an increased risk of cancer. Moreover, the same relationship was found when the studies were stratified by cancer type, ethnicity and source of controls.

Functional single nucleotide polymorphism in C20orf54 modifies susceptibility to esophageal squamous cell carcinoma

The aim of this study was to explore the association of C20orf54 functional single nucleotide polymorphism (SNP) with the susceptibility to esophageal squamous cell carcinoma (ESCC) in a northern China population. The C20orf54 SNP was genotyped by direct sequencing in 240 cancer patients and 198 controls in northern China. The results showed that drinking status, family history of ESCC, and body mass index have great influence on the risk of developing ESCC. The overall genotype frequencies of C20orf54 in ESCC patients have a significant difference with healthy controls (χ(2)  = 8.06, P = 0.018). By using C/C genotype as the reference, the C/T genotype showed a significantly decreased risk to the development of ESCC. Thus, compared with the C/C genotype, smokers, drinkers with C/T genotype significantly decreased the risk of developing ESCC. A positive family history of ESCC with C/T and T/T genotype both increased the risk of developing ESCC. Body mass index between 18.5 and 24 with C/T genotype significantly decreased the risk of developing ESCC. The present study suggests that the C20orf54 functional SNP might be associated with a risk of development in ESCC.

HLA-DRB1*1501 and HLA-DQB1*0301 alleles are positively associated with HPV16 infection-related Kazakh esophageal squamous cell carcinoma in Xinjiang China

Multiple determinant factors are involved in the occurrence and progression of esophageal squamous cell carcinoma (ESCC). Human papillomavirus (HPV) and human leukocyte antigen (HLA) polymorphism were identified as important factors. This study examined the associations between the development of Kazakh ESCC and the determinant factors including HLA-DRB1*0901, 1501; DQB1*0301, 0602; high-risk HPV infection in the area of Xinjiang, China. 200 Kazakh patients with ESCC and 150 controls were recruited, and polymerase chain reaction (PCR) was performed to detect HLA-DRB1*0901, 1501 and DQB1*0301,0602 using sequence-specific primers (SSPs). HPV16 was detected in esophageal specimens using PCR. HPV16 infection rate in Kazakh ESCC case group was 41 %, significantly higher than that of control group 14 % (OR = 3.62; 95 % CI, 2.15-6.09; P < 0.001). A positive association between ESCC and HLA-DRB1*1501 (OR = 2.46, P < 0.0125) or HLA-DQB1*0301 (OR = 3.34, P < 0.0125) alleles was observed. Similar tendencies were observed for HLA-DRB1*1501 (OR = 3.095, P < 0.0125) and HLA-DQB1*0301 (OR = 2.410, P < 0.0125) alleles with HPV16-positive ESCC. HLA-DRB1*1501, HLA-DQB1*0301 and DQB1*0602 were significantly associated with ESCC when the age was ≥55 years (P < 0.0125 for all), whereas only HLA-DQB1*0301 was significantly associated with ESCC when the age was <55 years (P < 0.0125). HLA-DRB1*1501 and HLA-DQB1*0301 were significantly associated with an increase in ESCC occurrence in females (P < 0.0125), whereas only HLA-DQB1*0301 was significantly associated with ESCC in males. Moreover, the occurrence of HLA-DQB1*0602 gene in poorly differentiated ESCC group (68.8 %) was slightly higher than that of well-differentiated squamous cell carcinoma group (31.2 %). The difference was not statistically significant (P > 0.0125). The study suggests that HLA-DRB1*1501 and HLA-DQB1*0301 may influence the immune response to specific tumor and HPV-encoded epitopes and affect the risk of Kazakh ESCC in XinJiang, China.

The cumulative effects of polymorphisms in the DNA mismatch repair genes and tobacco smoking in oesophageal cancer risk

The DNA mismatch repair (MMR) enzymes repair errors in DNA that occur during normal DNA metabolism or are induced by certain cancer-contributing exposures. We assessed the association between 10 single-nucleotide polymorphisms (SNPs) in 5 MMR genes and oesophageal cancer risk in South Africans. Prior to genotyping, SNPs were selected from the HapMap database, based on their significantly different genotypic distributions between European ancestry populations and four HapMap populations of African origin. In the Mixed Ancestry group, the MSH3 rs26279 G/G versus A/A or A/G genotype was positively associated with cancer (OR = 2.71; 95% CI: 1.34–5.50). Similar associations were observed for PMS1 rs5742938 (GG versus AA or AG: OR = 1.73; 95% CI: 1.07–2.79) and MLH3 rs28756991 (AA or GA versus GG: OR = 2.07; 95% IC: 1.04–4.12). In Black individuals, however, no association between MMR polymorhisms and cancer risk was observed in individual SNP analysis. The interactions between MMR genes were evaluated using the model-based multifactor-dimensionality reduction approach, which showed a significant genetic interaction between SNPs in MSH2, MSH3 and PMS1 genes in Black and Mixed Ancestry subjects, respectively. The data also implies that pathogenesis of common polymorphisms in MMR genes is influenced by exposure to tobacco smoke. In conclusion, our findings suggest that common polymorphisms in MMR genes and/or their combined effects might be involved in the aetiology of oesophageal cancer.

Epidemiologic differences in esophageal cancer between Asian and Western populations

Esophageal cancer is a common cancer worldwide and has a poor prognosis. The incidence of esophageal squamous cell cancer has been decreasing, whereas the incidence of esophageal adenocarcinoma has been increasing rapidly, particularly in Western men. Squamous cell cancer continues to be the major type of esophageal cancer in Asia, and the main risk factors include tobacco smoking, alcohol consumption, hot beverage drinking, and poor nutrition. In contrast, esophageal adenocarcinoma predominately affects the whites, and the risk factors include smoking, obesity, and gastroesophageal reflux disease. In addition, Asians and Caucasians may have different susceptibilities to esophageal cancer due to different heritage backgrounds. However, comparison studies between these two populations are limited and need to be addressed in the near future. Ethnic differences should be taken into account in preventive and clinical practices.

Validation of genetic sequence variants as prognostic factors in early-stage head and neck squamous cell cancer survival

PURPOSE

From the published literature, we identified 23 germ line sequence variants in 17 genes from hypothesis-generating studies that were associated with prognosis of head and neck cancer, including sequence variants of DNA repair (ERCC1, ERCC4, ERCC5, MSH2, XPA, ERCC2, XRCC1, XRCC3), DNA methylation (DNMT3B), cell cycle and proliferation (CCND1, TP53), xenobiotic metabolism (GSTM1, GSTT1, CYP2D6), metastatic -potential (MMP3), immunologic (CTLA4), and growth factor pathways (FGFR4). The purpose of this study was to validate the role of these 23 sequence variants for overall (OS) and disease-free survival (DFS) in a large, comprehensive, well-annotated data set of patients with head and neck cancer.

EXPERIMENTAL DESIGN

We genotyped these sequence variants in 531 patients with stage I and II radiation-treated head and neck cancer (originally recruited for an alpha-tocopherol/beta-carotene placebo-controlled secondary prevention study), and analyzed using Cox proportional hazards models, stratified by treatment arm, adjusting for clinical prognostic factors.

RESULTS

Two OS associations were statistically significant for each variant allele when compared with the wild-type: CTLA4: A49G [rs231775; adjusted HR (aHR), 1.32 (1.1-1.6); P = 0.01] and XRCC1: Arg339Gln [rs25487; aHR, 1.28 (1.05-1.57); P = 0.02]. Both of these sequence variants had significant results in the opposite direction as prior published literature. Two DFS associations were of borderline significance in the same direction as prior literature: ERCC2: Lys751Gln [rs13181; aHR, 0.80 (0.6-1.0); P = 0.05] and TP53: Arg72Pro [rs1042522; aHR, 1.28 (1.0-1.6); P = 0.03], comparing number of variant alleles with reference of zero variants.

CONCLUSIONS

None of the prognostic sequence variants previously published was validated for OS in our patients with early-stage radiation-treated head and neck cancer, though rs1381and rs1042522 had borderline significant association with DFS.

Interactions between environmental factors and polymorphisms in angiogenesis pathway genes in esophageal adenocarcinoma risk: a case-only study

BACKGROUND

Gastroesophageal reflux disease (GERD), higher body mass index (BMI), smoking, and genetic variants in angiogenic pathway genes have been individually associated with increased risk of esophageal adenocarcinoma. However, how angiogenic gene polymorphisms and environmental factors jointly affect esophageal adenocarcinoma development remains unclear.

METHODS

By using a case-only design (n = 335), the authors examined interactions between 141 functional/tagging angiogenic single nucleotide polymorphisms (SNPs) and environmental factors (GERD, BMI, smoking) in modulating esophageal adenocarcinoma risk. Gene-environment interactions were assessed by a 2-step approach. First, the authors applied random forest to screen for important SNPs that had either main or interaction effects. Second, they used case-only logistic regression to assess the effects of gene-environment interactions on esophageal adenocarcinoma risk, adjusting for covariates and false-discovery rate.

RESULTS

Random forest analyses identified 3 sets of SNPs (17 SNPs-GERD, 26 SNPs-smoking, and 34 SNPs-BMI) that had the highest importance scores. In subsequent logistic regression analyses, interactions between 2 SNPs (rs2295778 of HIF1AN, rs13337626 of TSC2) and GERD, 2 SNPs (rs2295778 of HIF1AN, rs2296188 of VEGFR1) and smoking, and 7 SNPs (rs2114039 of PDGRFA, rs2296188 of VEGFR1, rs11941492 of VEGFR1, rs17708574 of PDGFRB, rs7324547 of VEGFR1, rs17619601 of VEGFR1, and rs17625898 of VEGFR1) and BMI were significantly associated with esophageal adenocarcinoma development (all false-discovery rates ≤0.10). Moreover, these interactions tended to have SNP dose-response effects for increased esophageal adenocarcinoma risk with increasing number of combined risk genotypes.

CONCLUSIONS

These findings suggest that genetic variations in angiogenic genes may modify esophageal adenocarcinoma susceptibility through interactions with environmental factors in an SNP dose-response manner.

Association between polymorphisms in cancer-related genes and early onset of esophageal adenocarcinoma

There is an increasing incidence of esophageal adenocarcinoma (EA) among younger people in the western populations. However, the association between genetic polymorphisms and the age of EA onset is unclear. In this study, 1330 functional/tagging single-nucleotide polymorphisms (SNPs) from 354 cancer-related genes were genotyped in 335 white EA patients. Twenty important SNPs that have the highest importance scores and lowest classification error rate were identified by the random forest algorithm to be associated with early onset of EA (age ≤ 55 years). Subsequent logistic regression analysis indicated that 10 SNPs (rs2070744 of NOS3, rs720321 of BCL2, rs17757541 of BCL2, rs11775256 of TNFRSF10A, rs1035142 of CASP8, rs2236302 of MMP14, rs4740363 of ABL1, rs696217 of GHRL, rs2445762 of CYP19A1, and rs11941492 of VEGFR2/KDR) were significantly associated with early onset of EA (≤55 vs >55 years, all P < .05 after adjusting for co-variates and false discovery rate). Among them, five SNPs in the NOS3, BCL2, TNFRSF10A, and CASP8 genes were known to be involved in apoptosis processes. In Kaplan-Meier analyses, rs2070744 of NOS3, rs720321 of BCL2, and rs1035142 of CASP8 were also significantly associated with early onset of EA. Moreover, there was a higher risk of developing EA at a younger age when one had more risk genotypes. In conclusion, polymorphisms in cancer-related genes, especially those in the apoptotic pathway, play an important role in the development of younger-aged EA in a dose-response manner.

Upper gastrointestinal cancer predisposition syndromes

Malignancies of the upper gastrointestinal tract form a heterogeneous group of cancers characterized by unique epidemiology and biology. Despite these differences, survival for advanced disease remains poor across the panel of diseases, from cancers of the esophagus, stomach, pancreas, and, until recently, even gastrointestinal stromal tumors. Genetic predisposition syndromes associated with these diseases comprise an emerging subset of these diseases that may provide valuable information on cause and etiology. They may provide insight into molecular drivers for the disease, or disease subtypes, and also insights into novel gene/environment interactions. This review summarizes the current understanding of genetic predisposition syndromes of cancers of the upper gastrointestinal tract.

Genome-wide association study of esophageal squamous cell carcinoma in Chinese subjects identifies susceptibility loci at PLCE1 and C20orf54

We performed a genome-wide association study of esophageal squamous cell carcinoma (ESCC) by genotyping 1,077 individuals with ESCC and 1,733 control subjects of Chinese Han descent. We selected 18 promising SNPs for replication in an additional 7,673 cases of ESCC and 11,013 control subjects of Chinese Han descent and 303 cases of ESCC and 537 control subjects of Chinese Uygur-Kazakh descent. We identified two previously unknown susceptibility loci for ESCC: PLCE1 at 10q23 (P(Han combined for ESCC) = 7.46 x 10(-56), odds ratio (OR) = 1.43; P(Uygur-Kazakh for ESCC) = 5.70 x 10(-4), OR = 1.53) and C20orf54 at 20p13 (P(Han combined for ESCC) = 1.21 x 10(-11), OR = 0.86; P(Uygur-Kazakh for ESCC) = 7.88 x 10(-3), OR = 0.66). We also confirmed association in 2,766 cases of gastric cardia adenocarcinoma cases and the same 11,013 control subjects (PLCE1, P(Han for GCA) = 1.74 x 10(-39), OR = 1.55 and C20orf54, P(Han for GCA) = 3.02 x 10(-3), OR = 0.91). PLCE1 and C20orf54 have important biological implications for both ESCC and GCA. PLCE1 might regulate cell growth, differentiation, apoptosis and angiogenesis. C20orf54 is responsible for transporting riboflavin, and deficiency of riboflavin has been documented as a risk factor for ESCC and GCA.

Secondary prevention of esophageal squamous cell carcinoma in areas where smoking, alcohol, and betel quid chewing are prevalent

Esophageal cancer is ranked as the sixth most common cause of cancer death worldwide and has a substantial effect on public health. In contrast to adenocarcinoma arising from Barrett's esophagus in Western countries, the major disease phenotype in the Asia-Pacific region is esophageal squamous cell carcinoma which is attributed to the prevalence of smoking, alcohol, and betel quid chewing. Despite a multidisciplinary approach to treating esophageal cancer, the outcome remains poor. Moreover, field cancerization reveals that esophageal squamous cell carcinoma is closely linked with the development of head and neck cancers that further sub-optimize the treatment of patients. Therefore, preventive strategies are of paramount importance to improve the prognosis of this dismal disease. Since obstacles exist for primary prevention via risk factor elimination, the current rationale for esophageal cancer prevention is to identify high-risk groups at earlier stages of the disease, and encourage them to get a confirmatory diagnosis, prompt treatment, and intensive surveillance for secondary prevention. Novel biomarkers for identifying specific at-risk populations are under extensive investigation. Advances in image-enhanced endoscopy do not just substantially improve our ability to identify small precancerous or cancerous foci, but can also accurately predict their invasiveness. Research input from the basic sciences should be translated into preventive measures in order to decrease the disease burden of esophageal cancer.

Germline genetic variation, cancer outcome, and pharmacogenetics

Studies of the role of germline or inherited genetic variation on cancer outcome can fall into three distinct categories. First, the impact of highly penetrant but lowly prevalent mutations of germline DNA on cancer prognosis has been studied extensively for BRCA1 and BRCA2 mutations as well as mutations related to hereditary nonpolyposis colorectal cancer syndrome. These mainly modest-sized analyses have produced conflicting results. Although some associations have been observed, they may not be independent of other known clinical or molecular prognostic factors. Second, the impact of germline polymorphisms on cancer prognosis is a burgeoning field of research. However, a deeper understanding of potentially confounding somatic changes and larger multi-institutional, multistage studies may be needed before consistent results are seen. Third, research examining the impact of germline genetic variation on differential treatment response or toxicity (pharmacogenetics) has produced some proof-of-principle results. Putative germline pharmacogenetic predictors of outcome include DPYD polymorphisms and fluorouracil toxicity, UGT1A1 variation and irinotecan toxicity, and CYP2D6 polymorphisms and tamoxifen efficacy, with emerging data on predictors of molecularly targeted or biologic drugs. Here we review data pertaining to these germline outcome and germline toxicity relationships.

A Large-scale genetic association study of esophageal adenocarcinoma risk

The incidence of esophageal adenocarcinoma (EA) has been increasing rapidly, particularly among white males, over the past few decades in the USA. However, the etiology of EA and the striking male predominance is not fully explained by known risk factors. To identify susceptible genes for EA risk, we conducted a pathway-based candidate gene association study on 335 Caucasian EA cases and 319 Caucasian controls. A total of 1330 single-nucleotide polymorphisms (SNPs) selected from 354 genes were analyzed using an Illumina GoldenGate assay. The genotyped common SNPs include missense and exonic SNPs, SNPs within untranslated regions and 2 kb 5' of the gene, and tagSNPs for genes with little functional information available. Logistic regression adjusted for potential confounders was used to assess the genetic effect of each SNP on EA risk. We also tested gene-gender interactions using the likelihood ratio tests. We found that the genetic variants in the apoptosis pathway were significantly associated with EA risk after correcting for multiple comparisons. SNPs of rs3127075 in Caspase-7 (CASP7) and rs4661636 in Caspase-9 (CASP9) genes that play a critical role in apoptosis were found to be associated with an increased risk of EA. A protective effect of SNP rs572483 in the progesterone receptor (PGR) gene was observed among women carrying the variant G allele [adjusted odds ratio (OR) = 0.19; 95% confidence interval (CI) = 0.08-0.46] but was not observed among men (adjusted OR = 1.38; 95% CI = 0.95-2.00). In conclusion, this study suggests that the genetic variants of CASP7 and CASP9 in the apoptosis pathway may be important predictive markers for EA susceptibility and that PGR in the sex hormone signaling pathway may be associated with the gender differences in EA risk.