We conducted a genome-wide association study of gastric cancer (GC) and esophageal squamous cell carcinoma (ESCC) in ethnic Chinese subjects in which we genotyped 551,152 single nucleotide polymorphisms (SNPs). We report a combined analysis of 2,240 GC cases, 2,115 ESCC cases, and 3,302 controls drawn from five studies. In logistic regression models adjusted for age, sex, and study, multiple variants at 10q23 had genome-wide significance for GC and ESCC independently. A notable signal was rs2274223, a nonsynonymous SNP located in PLCE1, for GC (P=8.40×1010; per allele odds ratio (OR) = 1.31) and ESCC (P=3.85×10−9; OR = 1.34). The association with GC differed by anatomic subsite. For tumors located in the cardia the association was stronger (P=4.19 × 10−15; OR= 1.57) and for those located in the noncardia stomach it was absent (P=0.44; OR=1.05). Our findings at 10q23 could provide insight into the high incidence rates of both cancers in China.
Background And Objective
Two recent genome-wide association studies have identified a shared susceptibility variation PLCE1 rs2274223 for esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinomas (GCA). Subsequent case-control studies have reported this association in other populations. However, the findings were controversial and the effect remains undetermined. Our aim is to provide a precise quantification of the association between PLCE1 rs2274223 variation and the risk of ESCC and GCA.
Studies were identified by a literature search in MEDLINE and EMBASE databases. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association in allele, dominant, recessive, homozygous, and heterozygous models.
Ten articles were identified, including 22156 ESCC cases and 28803 controls, 5197 GCA cases and 17613 controls. Overall, PLCE1 rs2274223 G allele (G vs. A: OR=1.26, 95% CI: 1.15-1.39 for ESCC; OR=1.51, 95% CI: 1.35–1.69 for GCA) and its carrier (GG +AG vs. AA: OR = 1.23; 95% CI =1.02-1.49 for ESCC; OR =1.62; 95% CI =1.15-2.29 for GCA) were significantly associated with the risk of ESCC and GCA. In stratified analysis by ethnicity, significant association of PLCE1 rs2274223 G allele and the risk of ESCC (OR=1.33, 95% CI 1.21–1.45) and GCA (OR =1.56, 95% CI: 1.47-1.64) was observed in Chinese population.
Our meta-analysis results indicated that PLCE1 rs2274223 G allele significantly contributed to the risk of ESCC and GCA, especially in Chinese population.
Phospholipase C epsilon 1 (PLCE1) (an effector of Ras) belonging to the phospholipase family plays crucial roles in carcinogenesis and progression of several cancers, including squamous cell carcinoma of the head and neck (SCCHN). A single nucleotide polymorphism (SNP, rs2274223) in PLCE1 has been identified as a novel susceptibility locus in genome-wide association studies (GWAS) of esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinoma (GCA) that share similar risk factors with SCCHN. Therefore, we investigated the association between potentially functional SNPs in PLCE1 and susceptibility to SCCHN.
We genotyped three potentially functional SNPs (rs2274223A/G, rs3203713A/G and rs11599672T/G) of PLCE1 in 1,098 SCCHN patients and 1,090 controls matched by age and sex in a non-Hispanic white population.
Although none of three SNPs was alone significantly associated with overall risk of SCCHN, their combined effects of risk alleles (rs2274223G, rs3203713G and rs11599672G) were found to be associated with risk of SCCHN in a locus-dose effect manner (Ptrend = 0.046), particularly for non-oropharyngeal tumors (Ptrend = 0.017); specifically, rs2274223 was associated with a significantly increased risk (AG vs. AA: adjusted OR = 1.29, 95% CI = 1.01-1.64; AG/GG vs. AA: adjusted OR = 1.30, 95% CI = 1.03-1.64), while rs11599672 was associated with a significantly decreased risk (GG vs. TT: adjusted OR = 0.54, 95% CI = 0.34-0.86; TG/GG vs. TT: adjusted OR = 0.76, 95% CI = 0.61-0.95).
Our findings suggest that PLCE1 variants may have an effect on risk of SCCHN associated with tobacco and alcohol exposure, particularly for those tumors arising at non-oropharyngeal sites. These findings, although need to be validated by larger studies, are consistent with those in esophageal and gastric cancers.
PLCE1; polymorphism; SCCHN; risk; susceptibility
Germline genetic variants in PLCE1 (10q23) have demonstrated consistent associations with risk of esophageal squamous cell carcinoma (ESCC) and gastric cancer among Chinese. We evaluated PLCE1 mRNA and protein expression in paired tumor-normal tissues, and their relationship with survival.
PLCE1 mRNA was profiled using three probes in the Affymetrix GeneChip U133 for paired tumor-normal tissues of ESCC (n=132), gastric cardia adenocarcinoma (GCA, n=62) and gastric noncardia adenocarcinoma (GNCA, n=72). We used immunohistochemistry to detect PLCE1 protein on slides from tissue microarrays in paired tumor-normal tissues of ESCC (n=303), and tumors of GCA (n=298) and GNCA (n=124).
Compared with normal tissues, PLCE1 mRNA expression was significantly reduced in ESCC tumors (P=0.03, probe_205112_at), as well as in GCA and GNCA tumors (P<0.0001, each probe). Protein expression was non-significantly reduced in ESCC tumors (P=0.51). Increased tumor-normal mRNA fold change (probe_205112_at) was associated with longer survival in ESCC (9.6 months for highest vs lowest quartile; P-trend=0.02). Increased mRNA tumor-normal fold change (probe_205111_at) was associated with longer survival for GCA (10.7 months for highest quartile; P-trend=0.04), but not for GNCA cases (P=0.72). Similar to mRNA, elevated tumor-normal fold change for protein in ESCC was also associated with improved survival (8.1 months for highest quartile; P-trend=0.04).
Dysregulated PLCE1 mRNA expression was observed for both ESCC (one probe only) and GCA tumors, and the altered PLCE1 expression appears to be associated with cancer prognosis.
A potential role for PLCE1 in the early detection and/or therapy of ESCC and GCA warrants further investigation.
In recent years, the PLCE1 rs2274223 polymorphism has been extensively investigated as a potential risk factor for upper gastrointestinal cancers, including squamous cell carcinoma (ESCC) and gastric cancer. However, the results of these studies have been inconsistent.
A meta-analysis of 13 case-control studies was performed including more than 11,000 subjects with genotyped PLCE1 rs2274223 polymorphisms. Odds ratios (OR) with 95% confidence intervals (CI) were employed to assess the association of the PLCE1 rs2274223 polymorphism with a susceptibility to ESCC or gastric cancer.
A statistically significant increase in the risk of ESCC was associated with the PLCE1 rs2274223 polymorphism. This included the homozygous genetic model (OR = 1.46), heterozygous genetic model (OR = 1.25) and allelic genetic model (OR = 1.23). Similar results were consistently found for gastric cancer. In a subgroup analysis, the PLCE1 rs2274223 polymorphism was found to be a very sensitive marker for gastric cardia cancer as shown by the homozygous genetic model (OR = 2.23), heterozygous genetic model(OR = 1.59) and allelic genetic model (OR = 1.47). The risk associations of all of the gastric cardia cancer models were statistically significant. In contrast, none of the genetic models for non-cardia gastric cancer were significant.
In this meta-analysis, the PLCE1 rs2274223 polymorphism was confirmed to have a statistically significant association with an increasing risk of ESCC and gastric cancer. The increase risk was especially observed for gastric cardia cancer.
Phospholipase C epsilon 1 (PLCE1) plays an important role in cell growth, differentiation and oncogenesis. An increasing number of individual studies have investigated the association between PLCE1 rs2274223 polymorphism and cancer risk, but the conclusions are inconclusive. To obtain a comprehensive conclusion, we performed a meta-analysis of 22 studies with 13188 cases and 14666 controls. The pooled results indicated that PLCE1 rs2274223 A > G polymorphism was associated with an increased risk of overall cancer (G vs. A: OR = 1.15, 95% CI = 1.06–1.25; GG vs. AA: OR = 1.30, 95% CI = 1.10–1.55; GA vs. AA: OR = 1.18, 95% CI = 1.08–1.30; GG/GA vs. AA: OR = 1.20, 95% CI = 1.08–1.32; GG vs. GA/AA: OR = 1.22, 95% CI = 1.04–1.42). The stratification analysis showed the polymorphism was significantly associated with an increased risk of esophageal squamous cell carcinoma (ESCC) other than gastric cancer (GC), especially among the subgroups of Asian, high quality score, sample size > 1000 and the studies consistent with Hardy-Weinberg equilibrium (HWE). This meta-analysis demonstrated that PLCE1 rs2274223 A > G polymorphism may be associated with increased susceptibility to cancer, especially for ESCC. However, due to the substantial heterogeneities across the studies, the conclusion might be not conclusive that need more studies to confirm.
We previously showed that human papillomavirus (HPV) serostatus was not an independent risk factor for esophageal squamous cell carcinoma(ESCC) in nonsmokers and nondrinkers; however, HPV increased the risk in smokers.
Here we investigated possible interactions between HPV16 serostatus and three susceptibility loci identified in GWASs at apoptosis associated genes with regard to risk of ESCC in a case–control study of 313 patients with ESCC and 314 healthy controls. The loci (CHK2 rs738722, C12orf51 rs2074356, and PLCE1 rs2274223) were genotyped, and the presence or absence of HPV16 in serum was measured by ELISA. Multivariable logistic regression was used to evaluate possible interactions of HPV16 serostatus and the three loci on the risk of ESCC.
A significant interaction was found between HPV16 serology and rs2074356 (P = 0.005, odds ratio [OR] 1.40, 95% confidence interval [CI] 1.11–1.77) or rs2274223 (P < 0.001, OR 1.53, 95% CI 1.23–1.91), but not for rs738722. For rs2074356, risk of ESCC was increased substantially in smokers (P < 0.001, OR 8.25, 95% CI 3.84–17.71) and drinkers (OR4.04, P = 0.001, 95% CI 1.79–9.10) who carried risk alleles (TT or TC genotype) and were HPV16-seropositive. Similar results were observed for rs2274223 in smokers (P < 0.001, OR6.06, 95% CI 2.85–12.88) and drinkers (P < 0.001, OR 5.43, 95% CI 2.51–11.76), but not for rs738722.
Consistent with the previous study, loci at rs2074356 and rs2274223 could increase the risk of ESCC, furthermore, there were significant interactions between HPV sero-status and the susceptibility loci on the risk of ESCC. This effect could be modified obviously by smoking and drinking.
Esophageal squamous cell carcinoma; Apoptosis; Genome-wide association study; HPV16; Single nucleotide polymorphism; Smoking; Drinking
Recent genome-wide association studies (GWAS) have found a single nucleotide polymorphism (SNP, rs2274223 A>G) in PLCE1 to be associated with risk of gastric adenocarcinoma. In the present study, we validated this finding and also explored the risk associated with another unreported potentially functional SNP (rs11187870 G>C) of PLCE1 in a hospital-based case-control study of 1059 patients with pathologically confirmed gastric adenocarcinoma and 1240 frequency-matched healthy controls.
We determined genotypes of these two SNPs by the Taqman assay and used logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (95% CI). We found that a significant higher gastric adenocarcinoma risk was associated with rs2274223 variant G allele (adjusted OR = 1.35, 95% CI = 1.14–1.60 for AG+GG vs. AA) and rs11187870 variant C allele (adjusted OR = 1.26, 95% CI = 1.05–1.50 for CG+CC vs. GG). We also found that the number of combined risk alleles (i.e., rs2274223G and rs11187870C) was associated with risk of gastric adenocarcinoma in an allele-dose effect manner (Ptrend = 0.0002). Stratification analysis indicated that the combined effect of rs2274223G and rs11187870C variant alleles was more evident in subgroups of males, non-smokers, non-drinkers and patients with gastric cardia adenocarcinoma. Further real-time PCR results showed that expression levels of PLCE1 mRNA were significantly lower in tumors than in adjacent noncancerous tissues (0.019±0.002 vs. 0.008±0.001, P<0.05).
Our results further confirmed that genetic variations in PLCE1 may contribute to gastric adenocarcinoma risk in an eastern Chinese population.
The DNA repair pathways help to maintain genomic integrity and therefore genetic variation in the pathways could affect the propensity to develop cancer. Selected germline single nucleotide polymorphisms (SNPs) in the pathways have been associated with esophageal cancer and gastric cancer (GC) but few studies have comprehensively examined the pathway genes. We aimed to investigate associations between DNA repair pathway genes and risk of esophageal squamous cell carcinoma (ESCC) and GC, using data from a genome-wide association study in a Han Chinese population where ESCC and GC are the predominant cancers. In sum, 1942 ESCC cases, 1758 GC cases and 2111 controls from the Shanxi Upper Gastrointestinal Cancer Genetics Project (discovery set) and the Linxian Nutrition Intervention Trials (replication set) were genotyped for 1675 SNPs in 170 DNA repair-related genes. Logistic regression models were applied to evaluate SNP-level associations. Gene- and pathway-level associations were determined using the resampling-based adaptive rank-truncated product approach. The DNA repair pathways overall were significantly associated with risk of ESCC (P = 6.37 × 10−
4), but not with GC (P = 0.20). The most significant gene in ESCC was CHEK2 (P = 2.00 × 10−
6) and in GC was CLK2 (P = 3.02 × 10−
4). We observed several other genes significantly associated with either ESCC (SMUG1, TDG, TP53, GTF2H3, FEN1, POLQ, HEL308, RAD54B, MPG, FANCE and BRCA1) or GC risk (MRE11A, RAD54L and POLE) (P < 0.05). We provide evidence for an association between specific genes in the DNA repair pathways and the risk of ESCC and GC. Further studies are warranted to validate these associations and to investigate underlying mechanisms.
This study aimed to discover candidate single nucleotide polymorphisms (SNPs) for hypothesizing significant biological pathways of gastric cancer (GC). We performed an Identify Candidate Causal SNPs and Pathways (ICSNPathway) analysis using a GC genome-wide association study (GWAS) dataset, including 472,342 SNPs in 2,240 GC cases and 3,302 controls of Asian ethnicity. By integrating linkage disequilibrium analysis, functional SNP annotation, and pathway-based analysis, seven candidate SNPs, four genes and 12 pathways were selected. The ICSNPathway analysis produced 4 hypothetical mechanisms of GC: (1) rs4745 and rs12904 → EFNA1 → ephrin receptor binding; (2) rs1801019 → UMPS → drug and pyrimidine metabolism; (3) rs364897 → GBA → cyanoamino acid metabolism; and (4) rs11187870, rs2274223, and rs3765524 → PLCE1 → lipid biosynthetic process, regulation of cell growth, and cation homeostasis. This pathway analysis using GWAS dataset suggests that the 4 hypothetical biological mechanisms might contribute to GC susceptibility.
Genome-wide association study; Pathway-based analysis; Gastric cancer
The human major histocompatibility complex (MHC) is the most important region in vertebrate genome, and is crucial in innate immunity. Recent studies have demonstrated the possible role of polymorphisms in the MHC region to high risk for esophageal squamous cell carcinoma (ESCC). Our previous genome-wide association study (GWAS) has indicated that the MHC region may confer important risk loci for ESCC, but without further fine mapping. The aim of this study is to further identify the risk loci in the MHC region for ESCC in Chinese population.
Conditional logistic regression analysis (CLRA) was performed on 24 single nucleotide polymorphisms (SNPs) within the MHC region, which were obtained from the genetically matched 937 cases and 692 controls of Chinese Han population. The identified promising SNPs were further correlated with clinical and clinicopathology characteristics. Immunohistochemistry was performed to explore the protein expression pattern of the related genes in ESCC and neighboring normal tissues.
Of the 24 promising SNPs analyzed, we identified three independent SNPs in the MHC region associated with ESCC: rs35399661 (P = 6.07E-06, OR = 1.71, 95%CI = 1.36–2.17), rs3763338 (P = 1.62E-05, OR = 0.63, 95%CI = 0.50–0.78) and rs2844695 (P = 7.60E-05, OR = 0.74, 95%CI = 0.64–0.86). These three SNPs were located at the genes of HLA-DQA1, TRIM27, and DPCR1, respectively. Further analyses showed that rs2844695 was preferentially associated with younger ESCC cases (P = 0.009). The positive immunostaining rates both for HLA-DQA1 and TRIM27 were much higher in ESCC tissues than in neighboring normal tissues (69.4% vs. 26.8% for HLA-DQA1 and 77.6% vs. 47.8% for TRIM27, P<0.001). Furthermore, the overexpression of HLA-DQA1 is correlated significantly with age (P = 0.001) and family history (P<0.001).
This study for the first time provides evidence that multiple genetic factors within the MHC region confer risk to ESCC on the subjects from high-risk area in northern China.
Background & Aims
Diet could affect risk for esophageal and gastric cancers, but associations have been inconsistent. The diet is complex, so studies of dietary patterns, rather than studies of individual foods, might be more likely to identify cancer risk factors. There is limited research on index-based dietary patterns and esophageal and gastric cancers. We prospectively evaluated associations between the Healthy Eating Index-2005 (HEI-2005) and alternate Mediterranean Diet (aMED) scores and risk of esophageal and gastric cancers.
We analyzed data from 494,968 participants in the National Institutes of Health (NIH)-AARP Diet and Health study, in which AARP members (51–70 y old) completed a self-administered baseline food frequency questionnaire between 1995 and 1996. Their answers were used to estimate scores for each index.
During the follow-up period (1995–2006), participants developed 215 esophageal squamous cell carcinomas (ESCCs), 633 esophageal adenocarcinomas (EACs), 453 gastric cardia adenocarcinomas, and 501 gastric non-cardia adenocarcinomas. Higher scores from the HEI-2005 were associated with a reduced risk of ESCC (comparing the highest quintile with the lowest: hazard ratio [HR], 0.51; 95% confidence interval [CI], 0.31–0.86; Ptrend=.001) and EAC (HR, 0.75; 95% CI, 0.57–0.98; Ptrend=.01). We observed an inverse association between ESCC, but not EAC, and higher aMED score (meaning a higher-quality diet). HEI-2005 and aMED scores were not significantly associated with gastric cardia or noncardia adenocarcinomas.
Using data collected from 1995 through 2006 from the NIH-AARP Diet and Health Study, HEI-2005 and aMED scores were inversely associated with risk for esophageal cancers—particularly ESCC. Adherence to dietary recommendations might help prevent esophageal cancers.
food habits; esophageal neoplasms; stomach neoplasms
Recently, two large genome wide association studies, conducted in Chinese populations, reported associations between upper gastrointestinal (GI) cancer and the rs2274223, rs13042395 and rs4072037 polymorphisms in PLCE1, C20orf54 and MUC1 respectively. We set out to determine whether similar associations existed for Caucasian populations.
We genotyped two population-based, case-control studies of upper GI cancer; the first included 290 gastric cancer cases and 376 controls; the second study included 306 gastric cancer cases, 107 oesophageal adenocarcinoma cancer cases, 52 oesphageal squamous cell cancer cases, and 211 controls. Odds ratios (OR) and 95% confidence intervals (CI) were computed from logistic models and adjusted for confounding variables.
The rs4072037 polymorphism in MUC1 was associated with a reduced risk of gastric cancer of intestinal histological type (OR 0.4; 95% CI 0.2–0.9), and a reduced risk of oesophageal squamous cell cancer (OR 0.5; 95% CI 0.2–1.0), but not oesphageal adenocarcinoma. Likewise, rs2274223 in PLCE1 was associated with a reduced risk of oesophageal squamous cell cancer (OR 0.5; 95% CI 0.3–1.0) but not oesphageal adenocarcinoma. We observed no association between rs13042395 in Corf54 and risk of gastric or oesphageal cancer in either of the two studies.
Our findings for rs4072037 and gastric cancer risk are in keeping with one previous report for a Caucasian population. To the best of our knowledge this is the first study to report an association between rs2274223 and rs4072037 and risk of oesophageal squamous cell carcinoma in a Caucasian population.
The chromosome 9p21.3 region has been implicated in the pathogenesis of multiple cancers.
We systematically examined up to 203 tagging SNPs of 22 genes on 9p21.3 (19.9–32.8 Mb) in eight case–control studies: thyroid cancer, endometrial cancer (EC), renal cell carcinoma, colorectal cancer (CRC), colorectal adenoma (CA), oesophageal squamous cell carcinoma (ESCC), gastric cardia adenocarcinoma and osteosarcoma (OS). We used logistic regression to perform single SNP analyses for each study separately, adjusting for study-specific covariates. We combined SNP results across studies by fixed-effect meta-analyses and a newly developed subset-based statistical approach (ASSET). Gene-based P-values were obtained by the minP method using the Adaptive Rank Truncated Product program. We adjusted for multiple comparisons by Bonferroni correction.
Rs3731239 in cyclin-dependent kinase inhibitors 2A (CDKN2A) was significantly associated with ESCC (P=7 × 10−6). The CDKN2A-ESCC association was further supported by gene-based analyses (Pgene=0.0001). In the meta-analyses by ASSET, four SNPs (rs3731239 in CDKN2A, rs615552 and rs573687 in CDKN2B and rs564398 in CDKN2BAS) showed significant associations with ESCC and EC (P<2.46 × 10−4). One SNP in MTAP (methylthioadenosine phosphorylase) (rs7023329) that was previously associated with melanoma and nevi in multiple genome-wide association studies was associated with CRC, CA and OS by ASSET (P=0.007).
Our data indicate that genetic variants in CDKN2A, and possibly nearby genes, may be associated with ESCC and several other tumours, further highlighting the importance of 9p21.3 genetic variants in carcinogenesis.
common genetic variants; CDKN2A; 9p21.3
Low serum pepsinogen I (PGI) and low pepsinogen I/pepsinogen II ratio (PGI/II ratio) are markers of gastric fundic atrophy. We aimed to prospectively test the association between serum PGI/II ratio and risks of gastric noncardia adenocarcinoma, gastric cardia adenocarcinoma, and esophageal squamous cell carcinoma.
Case-cohort study nested in a prospective cohort with over 15 years of follow-up.
Rural region of the People’s Republic of China.
Men and women aged 40-69 at study baseline.
Main outcome measures
Adjusted hazard ratios and 95% confidence intervals for the association between serum PGI/II ratio and caner risk
Compared to subjects with PGI/II ratio of > 4, those with ≤4 had HRs (95%CIs) of 2.72 (1.77-4.20) and 2.12 (1.42-3.16) for noncardia and cardia gastric cancers, respectively. Risk of both cancers were also increased when other cut points ranging from 3 to 6, or when we used quartile models, or nonlinear continuous models. Risk of ESCC was marginally increased in those with PGI/II ratio ≤4, with HR (95% CI) of 1.56 (0.99-2.47), but quartile models and continuous models showed no increased risk. The nonlinear continuous models suggested that any single cut point collapsed subjects with dissimilar gastric cancer risks, and that using cut points was not an efficient use of data in evaluating these associations.
In this prospective study, we found similar and significantly increased risks of noncardia and cardia gastric adenocarcinomas in subjects with low PGI/II ratio, but little evidence for an association with ESCC risk.
Gastric cancer; Esophageal cancer; Pepsinogen; Case-cohort
Overexpression of Cyclooxygenase-2 (COX-2) was observed in many types of cancers, including esophageal squamous cell carcinoma (ESCC). One functional SNP, COX-2 -1195G/A, has been reported to mediate susceptibility of ESCC in Chinese populations. In our previous study, the presence of Helicobacter pylori (H. pylori) was found to play a protective role in development of ESCC. The interaction of COX-2 and H. pylori in gastric cancer was well investigated. However, literature on their interaction in ESCC risk is scarce. The purpose of this study was to evaluate the association and interaction between COX-2 single nucleotide polymorphism (SNP), H. pylori infection and the risk of developing ESCC.
One hundred and eighty patients with ESCC and 194 controls were enrolled in this study. Personal data regarding related risk factors, including alcohol consumption, smoking habits and betel quid chewing, were collected via questionnaire. Genotypes of the COX-2 -1195 polymorphism were determined by PCR-based restriction fragment length polymorphism. H. pylori seropositivity was defined by immunochromatographic screening test. Data was analyzed by chi-squared tests and polytomous logistics regression.
In analysis adjusting for the covariates and confounders, H. pylori seropositivity was found to be inversely association with the ESCC development (adjusted OR: 0.5, 95% CI: 0.3 – 0.9). COX-2 -1195 AA homozygous was associated with an increased risk of contracting ESCC in comparison with the non-AA group, especially among patients with H. pylori seronegative (adjusted OR ratio: 2.9, 95% CI: 1.2 – 7.3). The effect was strengthened among patients with lower third ESCC (adjusted OR ratio: 6.9, 95% CI 2.1 – 22.5). Besides, H. pylori seropositivity conveyed a notably inverse effect among patients with COX-2 AA polymorphism (AOR ratio: 0.3, 95% CI: 0.1 – 0.9), and the effect was observed to be enhanced for the lower third ESCC patients (AOR ratio: 0.09, 95% CI: 0.02 – 0.47, p for multiplicative interaction 0.008)
H. pylori seropositivity is inversely associated with the risk of ESCC in Taiwan, and COX-2 -1195 polymorphism plays a role in modifying the influence between H. pylori and ESCC, especially in lower third esophagus.
The role of tumor suppressor gene RASSF1A in the esophageal and gastric cardia carcinogenesis is still inconclusive. In this study, the polymorphism, promoter methylation and gene expression of RASSF1A were characterized in esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinoma (GCA).
We firstly analyzed the prevalence of RASSF1A A133S in a total of 228 cancer patients with ESCC (n=112) and GCA (n=116) and 235 normal controls by polymerase chain reaction (PCR) and restriction enzyme-digestion assay. Then, the promoter methylation status of the RASSF1A in ESCC (n=143), GCA (n=92) and corresponding adjacent normal tissues were further investigated using methylation-specific PCR (MSP) approach. Finally, the RASSF1A protein expression were determined in ESCC (n=27), GCA (n=24) and the matched adjacent normal tissues by immunohistochemical method.
The frequency of 133Ala/Se and Ser/Ser genotype was significantly higher in GCA patients than in normal controls (19.0% vs. 10.2%, P=0.02). Compared with Ala/Ala genotype, Ala/Se and Ser/Ser genotype significantly increased susceptibility to GCA (OR=2.06, 95% CI=1.09–3.97). However, this polymorphism had no association with ESCC (P=0.69). The promoter methylation of RASSF1A gene was significantly increased the risk to both ESCC (OR=5.90, 95% CI=2.78–12.52) and GCA (OR=7.50, 95% CI= 2.78–20.23). Promoter methylation of RASSF1A gene in ESCC was also associated with age and cancer cell differentiation (for age: OR=3.11, 95% CI=1.10–8.73; for differentiation: OR=0.29, 95% CI=0.12–0.69). RASSF1A positive expression was significantly decreased the risk of GCA (OR=0.16, 95% CI=0.03–0.83). In contrast, there was no statistical significance between RASSF1A positive expression and ESCC. The expression of RASSF1A protein trend to be positively related with older GCA patients (OR=16.20, 95% CI=1.57–167.74).
The present findings suggest that alterations of RASSF1A may play an important role in gastric cardia carcinogenesis in terms of polymorphism, promoter hypermethylation and protein expression. Whereas, RASSF1A hypermethylation may probably also be involved in esophageal squamous cell carcinogenesis.
Esophageal squamous cell carcinoma; Gastric cardia adenocarcinoma; A133S in RASSF1A; Polymorphism; Methylation; Protein expression
Esophageal squamous cell carcinoma (ESCC) is one of the most common fatal malignances of the digestive tract. Its prognosis is poor mainly due to the lack of reliable markers for early detection and prognostic prediction. Here we aim to identify the molecules involved in ESCC carcinogenesis and those as potential markers for prognosis and as new molecular therapeutic targets.
We performed genome-wide gene expression profile analyses of 10 primary ESCCs and their adjacent normal tissues by cDNA microarrays representing 47,000 transcripts and variants. Candidate genes were then validated by semi quantitative reverse transcription-PCR (RT-PCR), tissue microarrays (TMAs) and immunohistochemistry (IHC) staining.
Using an arbitrary cutoff line of signal log ratio of ≥1.5 or ≤−1.5, we observed 549 up-regulated genes and 766 down-regulated genes in ESCCs compared with normal esophageal tissues. The functions of 302 differentially expressed genes were associated with cell metabolism, cell adhesion and immune response. Several candidate deregulated genes including four overexpressed (CTTN, DMRT2, MCM10 and SCYA26) and two underexpressed (HMGCS2 and SORBS2) were subsequently verified, which can be served as biomarkers for ESCC. Moreover, overexpression of cortactin (CTTN) was observed in 126/198 (63.6%) of ESCC cases and was significantly associated with lymph node metastasis (P = 0.000), pathologic stage (P = 0.000) and poor survival (P<0.001) of ESCC patients. Furthermore, a significant correlation between CTTN overexpression and shorter disease-specific survival rate was found in different subgroups of ESCC patient stratified by the pathologic stage (P<0.05).
Our data provide valuable information for establishing molecules as candidates for prognostic and/or as therapeutic targets.
The epidermal growth factor receptor (EGFR) signaling pathway regulates cell proliferation, differentiation, and survival, and is frequently dysregulated in esophageal and gastric cancers. Few studies have comprehensively examined the association between germline genetic variants in the EGFR pathway and risk of esophageal and gastric cancers. Based on a genome-wide association study in a Han Chinese population, we examined 3443 SNPs in 127 genes in the EGFR pathway for 1942 esophageal squamous cell carcinomas (ESCCs), 1758 gastric cancers (GCs), and 2111 controls. SNP-level analyses were conducted using logistic regression models. We applied the resampling-based adaptive rank truncated product approach to determine the gene- and pathway-level associations. The EGFR pathway was significantly associated with GC risk (P = 2.16×10−3). Gene-level analyses found 10 genes to be associated with GC, including FYN, MAPK8, MAP2K4, GNAI3, MAP2K1, TLN1, PRLR, PLCG2, RPS6KB2, and PIK3R3 (P<0.05). For ESCC, we did not observe a significant pathway-level association (P = 0.72), but gene-level analyses suggested associations between GNAI3, CHRNE, PAK4, WASL, and ITCH, and ESCC (P<0.05). Our data suggest an association between specific genes in the EGFR signaling pathway and risk of GC and ESCC. Further studies are warranted to validate these associations and to investigate underlying mechanisms.
Esophageal squamous cell carcinoma (ESCC) has a high mortality rate. To determine the molecular basis of ESCC development, this study sought to identify characteristic genome-wide alterations in ESCC, including exonic mutations and structural alterations. The clinical implications of these genetic alterations were also analyzed. Exome sequencing and verification were performed for nine pairs of ESCC and the matched blood samples, followed by validation with additional samples using Sanger sequencing. Whole-genome SNP arrays were employed to detect copy number alteration (CNA) and loss of heterozygosity (LOH) in 55 cases, including the nine ESCC samples subjected to exome sequencing. A total of 108 non-synonymous somatic mutations (NSSMs) in 102 genes were verified in nine patients. The chromatin modification process was found to be enriched in our gene ontology (GO) analysis. Tumor genomes with TP53 mutations were significantly more unstable than those without TP53 mutations. In terms of the landscape of genomic alterations, deletion of 9p21.3 covering CDKN2A/2B (30.9%), amplification of 11q13.3 covering CCND1 (30.9%), and TP53 point mutation (50.9%) occurred in two-thirds of the cases. These results suggest that the deregulation of the G1 phase during the cell cycle is a key event in ESCC. Furthermore, six minimal common regions were found to be significantly altered in ESCC samples and three of them, 9p21.3, 7p11.2, and 3p12.1, were associated with lymph node metastasis. With the high correlation of TP53 mutation and genomic instability in ESCC, the amplification of CCND1, the deletion of CDKN2A/2B, and the somatic mutation of TP53 appear to play pivotal roles via G1 deregulation and therefore helps to classify this cancer into different genomic subtypes. These findings provide clinical significance that could be useful in future molecular diagnoses and therapeutic targeting.
Esophageal squamous cell carcinoma; Genomic subtype; Somatic mutation; Copy number alteration; Cell cycle deregulation
To date, the association between phospholipase C epsilon 1 (PLCE1) rs2274223 A>G and risk of digestive tract cancer (DTC) remains inconclusive. To derive a more precise estimation of the association, we conducted a meta-analysis on all eligible case–control studies involving 8281 cases and 10,532 controls.
A comprehensive search was conducted to identify all eligible studies of PLCE1 rs2274223 polymorphism and digestive tract cancer risk. The pooled odds ratio (OR) and the 95% confidence interval (95% CI) were calculated using a fixed or random effect model. Heterogeneity, publication bias, and sensitivity analysis were also explored.
Overall, the PLCE1 rs2274223 A>G polymorphism was associated with risk of DTC in all genetic models (GA vs. AA: OR = 1.21, 95% CI = 1.14–1.29, P<0.001; GG vs. AA: OR = 1.30, 95% CI = 1.06–1.60, P = 0.012; GG/GA vs. AA: OR = 1.20, 95% CI = 1.10–1.32, P<0.001; GG vs. GA/AA: OR = 1.21, 95% CI = 1.01–1.46, P = 0.040). The recessive model did not reach statistically significance when the P values were Bonferroni corrected to 0.0125. In the stratified analysis by cancer type, ethnicity, and source of controls, significantly increased risk was observed for esophagus cancer, Asians in three genetic models (heterozygote comparison, homozygote comparison and dominant model), population-based studies in all genetic models, and for gastric cancer in the heterozygote comparison and dominant model after Bonferroni correction. However, in the subsite of gastric cancer, no significant association was found either in cardia or non-cardia gastric cancer.
Our study indicated that PLCE1 rs2274223 A>G polymorphism was significantly associated with increased risk of DTC, especially among Asian populations. Due to some minor limitations, our findings should be confirmed in further studies.
China was one of the countries with highest esophageal squamous cell carcinoma (ESCC) incidence and mortality worldwide. Alcohol drinking has been identified as a major environmental risk-factor related to ESCC. The alcohol dehydrogenase (ADH) family are major enzymes involved in the alcohol-metabolizing pathways, including alcohol dehydrogenase 1B (ADH1B) and ADH1C. Interestingly, ADH1B and ADH1C genes locate tandemly with ADH7 in a genomic segment as a gene cluster, and are all polymorphic. Several ESCC susceptibility single nucleotide polymorphisms (SNPs) of the ADH1B-ADH1C-ADH7 cluster have been identified previously through a genome-wide association study (GWAS). In the study, we examined the association between five ADH1B-ADH1C-ADH7 cluster SNPs (rs1042026, rs17033, rs1614972, rs1789903 and rs17028973) and risk of developing ESCC. Genotypes were determined in two independent case-control sets from two regions of China. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression. Our data demonstrated that these ADH1B-ADH1C-ADH7 cluster SNPs confer susceptibility to ESCC in these two case-control sets, which were consistent to results of the previous GWAS.
In China, esophageal cancer is the fourth leading cause of cancer death where essentially all cases are histologically esophageal squamous cell carcinoma (ESCC), in contrast to esophageal adenocarcinoma in the West. Globally, ESCC is 2.4 times more common among men than women and recently it has been suggested that sex hormones may be associated with the risk of ESCC. We examined the association between genetic variants in sex hormone metabolic genes and ESCC risk in a population from north central China with high-incidence rates. A total of 1026 ESCC cases and 1452 controls were genotyped for 797 unique tag single-nucleotide polymorphisms (SNPs) in 51 sex hormone metabolic genes. SNP-, gene- and pathway-based associations with ESCC risk were evaluated using unconditional logistic regression adjusted for age, sex and geographical location and the adaptive rank truncated product (ARTP) method. Statistical significance was determined through use of permutation for pathway- and gene-based associations. No associations were observed for the overall sex hormone metabolic pathway (P = 0.14) or subpathways (androgen synthesis: P = 0.30, estrogen synthesis: P = 0.15 and estrogen removal: P = 0.19) with risk of ESCC. However, six individual genes (including SULT2B1, CYP1B1, CYP3A7, CYP3A5, SHBG and CYP11A1) were significantly associated with ESCC risk (P < 0.05). Our examination of genetic variation in the sex hormone metabolic pathway is consistent with a potential association with risk of ESCC. These positive findings warrant further evaluation in relation to ESCC risk and replication in other populations.
AIM: To investigate the possible association of G→A single nucleotide polymorphism (SNP) at the -1082 position of interleukin (IL)-10 promoter with susceptibility to esophageal squamous cell carcinoma (ESCC) and gastric cardiac adenocarcinoma (GCA) in a population of a high incidence region of North China.
METHODS: IL-10-G1082A promoter SNP was genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) in 355 cancer patients (203 ESCC and 152 GCA) and 443 healthy controls.
RESULTS: Smoking significantly increased the risk of ESCC and GCA development (the age and sex adjusted OR = 1.42 and 2.64, 95%CI = 1.11-1.81 and 1.46-4.76, respectively). Similarly, family history of upper gastrointestinal cancer (UGIC) significantly increased the risk of developing ESCC and GCA (the age and sex adjusted OR = 1.44 and 3.10, 95%CI = 1.18-1.75 and 1.94-4.97, respectively). The A/A, A/G and G/G genotype frequencies of IL-10-G1082A were 60.3%, 37.0% and 2.7% in healthy controls, 57.6%, 39.9% and 2.5% in ESCC and 61.2%, 36.8% and 2.0% in GCA patients, respectively. The frequencies of A and G alleles were 78.8% and 21.2% in healthy controls, 77.6% and 22.4% in ESCC patients and 79.6%, 20.4% in GCA patients. The distribution of genotype and allelotype in ESCC and GCA patients was not significantly different from that in healthy controls (P>0.05). Compared to the A/A genotype, the combination of A/G and G/G genotypes did not show a significant effect on the risk of developing ESCC and GCA; the adjusted odds ratio was 0.92 (95% CI = 0.76-1.11) in ESCC and 0.95 (95% CI = 0.61-1.46) in GCA, respectively. When stratified for smoking status and family history of UGIC, the combination of A/G and G/G genotypes also did not show any significant influence on the risk of ESCC and GCA development compared to A/A genotypes.
CONCLUSION: IL-10-G1082A polymorphism might not be used as a stratification marker to predicate the risk of ESCC and GCA development in North China.
Polymorphism; Esophageal squamous cell carcinoma; Gastric cardiac adenocarcinoma
Esophageal squamous cell carcinoma (ESCC) is a highly lethal cancer, and its underlying molecular mechanisms are poorly understood. Recent large-scale genome-wide association studies in Chinese Han populations have identified an ESCC susceptibility locus within the SLC39A6 gene. Here, we sought to explore the expression and biological function of SLC39A6 in ESCC.
Multiethnic validation of SLC39A6 protein expression was performed in different cohorts of patients from Chinese Han and Kazakh populations in the Xinjiang region by immunohistochemistry. The associations among SLC39A6 expression, clinicopathological parameters, and prognosis outcomes of ESCC were analyzed. And the effects of SLC39A6 silencing by siRNA on cell proliferation, apoptosis, and invasiveness, as well as the proteins involved in epithelial-to-mesenchymal transition (EMT) of esophageal cancer cells, were studied.
SLC39A6 protein expression increased progressively from normal esophageal epithelium (NEE) to low-grade intraepithelial neoplasia to ESCC, and finally reached the highest in high-grade intraepithelial neoplasia from Han ethnic. Similarly, SLC39A6 protein was significantly overexpressed in Kazakh ethnic ESCC compared with that in NEE. Increased expression of SLC39A6 was found to be closely correlated with histological grade and early Tumor-Node-Metastasis stage I/II. High tumorous SLC39A6 expression was significantly correlated with shorter overall survival (OS). Cox regression analysis confirmed that SLC39A6 expression was an independent prognostic factor for poor OS in ESCC. Experimentally, the suppression of SLC39A6 expression promoted ESCC cell apoptosis but abrogated proliferation and invasion, and induced an EMT phenotype that included enhanced expression of E-cadherin, loss of vimentin, and morphological changes in ESCC cells in vitro.
Combined, our findings highlight a tumor-promoting role for SLC39A6 in ESCC, suggesting that SLC39A6 could serve as an early detector of high-risk subjects and prognostic biomarker. The targeting of SLC39A6 might be a potential therapeutic strategy for blocking ESCC.
Electronic supplementary material
The online version of this article (doi:10.1186/s12967-015-0681-z) contains supplementary material, which is available to authorized users.
SLC39A6; ESCC; Precursor lesions; Prognosis