Replication study of PLCE1 and C20orf54 polymorphism and risk of esophageal cancer in a Chinese population

Identification and detection of plasma extracellular vesicles-derived biomarkers for esophageal squamous cell carcinoma diagnosis

Esophageal cancer is a malignant tumor with two-thirds of patients having a local recurrence or distant metastasis. To date, diagnostic biomarkers with high sensitivity and specificity are lacking. Extracellular vesicles (EVs) have shown their potential values as disease biomarkers as they carry specific proteins and RNAs derived from cancer cells. In this study, we investigate ESCC precision diagnostics from the insights of circulating EVs, and integrate the ultrafast EV isolation approach (EXODUS) and ELISA for fast detection and screening of ESCC patients. First, we isolate and characterize the high-purity plasma EVs with EXODUS and identify 401 proteins and 372 proteins from ESCC patient and healthy individuals, respectively. Further looking into the differentially expressed proteins (DEPs) of ESCC patients and enriched KEGG pathways, we discover EV-CD14 as a potential diagnostic biomarker for ESCC, which has been further validated as a significantly differentially expressed protein by Western Blot and immunogold labelling TEM. For fast screening and detection of ESCC towards clinical applications, we apply ELISA method to diagnose ESCC from 60 clinical samples based on circulating EV-CD14, which shows a high AUC value up to 96.0% for detection of ESCC in a test set (30 samples), and displays a high accuracy rate up to 90% for prediction of ESCC in a screening test (30 samples). Our results suggest that the circulating EV-CD14 may highly be related to the initiation and progression of ESCC, providing a novel method for the diagnosis and prognosis of ESCC towards clinical translations.

Functional variation of SLC52A3 rs13042395 predicts survival of Chinese gastric cancer patients

The solute carrier family 52 member 3 (SLC52A3) gene encodes riboflavin transporter protein which is essential to maintain mitochondrial function in cells. In our research, we found that SLC52A3 rs13042395 C > T variation was significantly associated with poor survival in a 926 Chinese gastric cancer (GCa) patients cohort (CC/CT genotype versus TT genotype, HR = 0.57, 95%CI (0.40‐0.82), log‐rank P = 0.015). The SLC52A3 rs13042395 C > T change led to its increased mRNA expression according to expression quantitative trait loci analysis (P = 0.0029). In vitro, it was revealed that rs13042395 C allele had higher binding affinity to inhibitory transcription factor Meis homeobox 1 (MEIS1) compared with T allele, knock‐down of MEIS1 could up‐regulate SLC52A3, and overexpression of SLC52A3 contributed to the increased ability of proliferation, colony formation, migration and invasion in GCa cells. Subsequently, the bioinformatics analysis combined with experiments in vitro suggested that Gap junction protein alpha 1 (GJA1) was the downstream effector of SLC52A3, SLC52A3 may promote the GCa cells aggressiveness by down‐regulating the GJA1 expression. Overall, SLC52A3 genetic variant rs13042395 C > T change was associated with poorer survival in Chinese GCa patients and increased SLC52A3 expression by interaction with MEIS1. SLC52A3 promoted the GCa cells aggressiveness by down‐regulating the GJA1 expression.

Long non-coding RNA CASC8 polymorphisms are associated with the risk of esophageal cancer in a Chinese population

Background

Esophageal cancer (EC) is an important disease that threatens public health and safety. Although there are numerous treatment options for esophageal cancer including surgery, radiation therapy, and chemotherapy, these treatments have limited effects. Its morbidity and mortality vary widely among countries and regions. Esophageal cancer is classified into squamous cell carcinoma (ESCC) and esopheageal adenocarcinoma (EADC). Here, we examined the genetic susceptibility to ESCC in relation to functional single nucleotide polymorphisms (SNPs) in the long non‐coding RNA (lncRNA) CASC8.

Methods

To detect the susceptibility to ESCC in relation to functional polymorphisms in CASC8, a hypothesis‐driven study was performed to identify CASC8 SNPs in 949 patients with ESCC and 1369 control subjects.

Results

The CASC8 rs1562430 GG genotype was significantly associated with increased ESCC risk in men, patients younger than 63 years, non‐smokers, and nondrinkers.

Conclusions

CASC8 rs1562430 A > G may cause susceptibility to ESCC and CASC8 SNPs may play a vital role in ESCC risk, thereby serving as a potential biomarker for diagnosing ESCC. A larger sample size and multifactor information are needed to confirm these results.

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.

An Association and Meta-Analysis of Esophageal Squamous Cell Carcinoma Risk Associated with PLCE1 rs2274223, C20orf54 rs13042395 and RUNX1 rs2014300 Polymorphisms

One of the highest risk of esophageal squamous cell carcinoma (ESCC) in the world has been reported in Iran, which is located in the Asian esophageal cancer belt. ESCC constitutes 90% of the esophageal cancer cases in Iran. Genome wide association studies (GWASs) in Chinese have identified a number of candidate variants, of which PLCE1rs2274223, C20orf54rs13042395 and RUNX1rs2014300 are studied in high risk populations including Chinese, Caucasians and Africans. However, results are inconsistent and it is unknown whether similar associations exist in Iranian population. We evaluated association of three GWAS identified variants with risk of ESCC in an Iranian cohort consisted of 200 ESCC patients and 300 healthy controls and conducted meta-analysis of ESCC risk associated with rs2274223 (involving 9810 cases and 13,128 controls) and rs13042395 (involving 2363 cases and 5329 controls). Logistic regression analysis showed that rs2274223 was associated with ESCC under codominant [GG/AA, 2.47(1.17-5.23), P:0.021], dominant [AG + GG/AA, 1.57(1.09-2.27), P:0.016], recessive [GG/AA+AG, 2.18(1.04-4.56), P:0.036] and log-additive models [1.51(1.12-2.02), P:0.006]. C20orf54 rs13042395 was not associated with ESCC under any genetic model. RUNX1 rs2014300 was associated with risk of ESCC assuming codominant [AG/GG, 0.63(0.41-0.97), P:0.018], dominant [AG + AA/GG, 0.59 (0.39-0.89), P:0.010] and log-additive models [0.61 (0.42-0.87), P: 0.005]. Meta-analysis found significant associations between rs2274223 and ESCC under all analyzed genetic models. However, meta-analysis stratified by ethnicity showed a significant association in Asians but not non-Asian populations. No significant association was found for rs13042395 in meta-analysis. This study provided first evidence for association of GWAS-identified variants with risk of ESCC in an Iranian cohort.

Single Nucleotide Polymorphisms in PLCE1 for Cancer Risk of Different Types: A Meta-Analysis

Background: Recent studies have investigated the relationships between PLCE1 polymorphisms and cancer susceptibility. However, some findings lack consistency.

Objectives: In the current study, we conducted a meta-analysis to more accurately evaluate the relationships between PLCE1 (rs2274223, rs3765524, rs753724, rs11187842, and rs7922612) single nucleotide polymorphisms (SNPs) and risk for different types of cancer.

Methods: We performed a comprehensive search strategy in PubMed, Web of Science, Medline, EMbase, and Scopus for articles available until 19 March 2018. A total of 54 case-control studies comprising 17,955 cases and 20,400 controls were included in the current meta-analysis, which together comprised a total of 32 publications. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate relationships between the PLCE1 polymorphisms and cancer susceptibility. All statistical analyses were performed using Stata 11 software.

Results: Results of the meta-analysis demonstrated that the rs2274223 polymorphism showed a significant correlation with increased overall cancer susceptibility (AG vs. AA: OR 1.168, 95% CI 1.084–1.259; GG vs. AA: OR 1.351, 95% CI 1.163–1.570; AG+GG vs. AA: OR 1.193, 95% CI 1.103–1.290; GG vs. AA+AG: OR 1.262, 95% CI 1.102–1.446; G vs. A: OR 1.163, 95% CI 1.089–1.242). Results of subgroup analysis showed that the rs2274223 polymorphism was associated with higher risk for esophageal cancer and gastric cancer relative to colorectal cancer and head and neck cancer. In addition, the rs2274223 polymorphism was found to be associated with increased cancer risk, especially among the subgroups comprising Asians, studies with population-based controls, studies employing the TaqMan genotyping method, and studies consistent with Hardy-Weinberg equilibrium (HWE). The association between the rs3765524 polymorphism and reduced overall cancer risk was detected in one specific genetic model (CT vs. CC: OR 0.681, 95% CI 0.523–0.886). Results of subgroup analysis showed that the rs3765524 polymorphism was associated with cancer risk in a specific genetic model among the subgroups of colorectal cancer, esophageal cancer, Asians, studies with population-based controls, and studies consistent with HWE. However, relationships among the PLCE1 rs753724, rs11187842, and rs7922612 polymorphisms and tumor risk were not identified.

Conclusions: Results of the current meta-analysis suggested that PLCE1 (rs2274223, rs3765524) polymorphisms are associated with cancer susceptibility.

PLCE1 Promotes the Invasion and Migration of Esophageal Cancer Cells by Up-Regulating the PKCα/NF-κB Pathway

PURPOSE

To investigate the effect and mechanism of phospholipase C epsilon gene 1 (PLCE1) expression on esophageal cancer cell lines.

MATERIALS AND METHODS

The esophageal carcinoma cell lines Eca109 and EC9706 and normal esophageal epithelial cell line HEEC were cultured. The expression of PLCE1, protein kinase C alpha (PKCα), and nuclear factor kappa B (NF-κB) p50/p65 homodimer in cells were comparatively analyzed. The esophageal cancer cells were divided into si-PLCE1, control siRNA (scramble), and mock groups that were transfected with specific siRNA for PLCE1, control siRNA, and blank controls, respectively. Expression of PLCE1, PKCα, p50, and p65 was detected by Western blotting. Transwell assay was used to detect migration and invasion of Eca109 and EC9706 cells.

RESULTS

Compared with HEEC, the expression of PLCE1, PKCα, p50, and p65 was increased in Eca109 and EC9706 cells. The expression of PLCE1 was positively correlated with the expression of PKCα and p50 (PKCα: r=0.6328, p=0.032; p50: r=0.6754, p=0.041). PKCα expression had a positive correlation with the expression of p50 and p65 (p50: r=0.9127, p=0.000; p65: r=0.9256, p=0.000). Down-regulation of PLCE1 significantly decreased the expression of PKCα and NF-κB-related proteins (p65: p=0.002, p=0.004; p50: p=0.005, p=0.009) and inhibited the migration and invasion of Eca109 and EC9706 cells.

CONCLUSION

PLCE1 activated NF-κB signaling by up-regulating PKCα, which could promote invasion and migration of esophageal cancer cells.

PLCE1 polymorphisms and expression combined with serum AFP level predicts survival of HBV-related hepatocellular carcinoma patients after hepatectomy

Polymorphisms in the phospholipase C epsilon (PLCE) 1 gene play a crucial role in the development and progression of several types of cancer. The present study investigated the prognostic significance of PLCE1 gene polymorphisms and expression combined with serum α-fetoprotein (AFP) level in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Single nucleotide polymorphisms were genotyped by sequencing DNA isolated from surgically resected tumor samples of 421 HBV-related HCC patients, and expression profiles were generated based on the GSE14520 dataset. A joint-effects analysis of PLCE1 haplotypes (Ars2274223Crs3765524; Grs2274223Trs3765524) with AFP level stratified at 20 ng/ml showed a significant association with overall survival(OS) of HBV-related HCC patients(log-rank P=0.0003). Patients with AC and GT haplotypes with AFP level ≥ 20 ng/ml had an increased risk of death as compared to those with the AC haplotype and AFP level < 20 ng/ml (adjusted P=0.029 and 0.041, respectively). Patients with the GT haplotype and AFP level < 20 ng/ml also had an increased risk of death, although with a non-significant P value (adjusted P=0.092). Joint-effects analysis of PLCE1 mRNA expression with serum AFP level stratified at 300 ng/ml was significantly associated with HBV-related HCC recurrence and OS. Our results demonstrate that PLCE1 haplotypes (including rs2274223 and rs3765524) and expression combined with serum AFP level may predict postoperative outcome of HBV-related HCC patients.

IL18 rs360719 A>G, IL18R1 rs13015714 G>T, IL18RAP rs917997 C>T and IL28B rs8099917 T>G polymorphisms and risk of gastric cardiac adenocarcinoma

The present study was conducted to investigate the association between gastric cardiac adenocarcinoma (GCA) and four functional single-nucleotide polymorphisms (SNPs), including interleukin 18 (IL18) rs360719 A>G, IL18 receptor 1 (IL18R1) rs13015714 G>T, IL18 receptor accessory protein (IL18RAP) rs917997 C>T and interleukin 28B (IL28B) rs8099917 T>G variants. A hospital-based case-control study was performed to evaluate the genetic effects of these SNPs. A total of 243 GCA cases and 476 controls were enrolled in this study. A custom-by-design 48-Plex SNPscan™ kit was used to determine the genotypes. When the IL18 rs360719 AA homozygote genotype was used as the reference group, the AG genotype was not associated with the risk for GCA; the GG genotype was also not associated with the risk for GCA. In the dominant model, the IL18 rs360719 AG/GG variants were not associated with the risk for GCA, compared with the IL18 rs360719 AA genotype. In the recessive model, when the IL18R1 rs13015714 AA/AG genotypes were used as the reference group, the GG homozygote genotype was not associated with risk for GCA. No association was observed between IL18R1 rs13015714 G>T, IL18RAP rs917997 C>T and IL28B rs8099917 T>G polymorphisms and the risk for GCA. These results demonstrated that the functional polymorphisms IL18 rs360719 A>G, IL18R1 rs13015714 G>T, IL18RAP rs917997 C>T and IL28B rs8099917 T>G do not contribute to GCA susceptibility. However, as the statistical power of our study was limited, large well-designed studies and further functional investigations are required to confirm our findings.

Phospholipase C ε-1 gene polymorphisms and prognosis of esophageal cancer patients from a high-incidence region in northern China

Recent genome-wide association studies identified susceptibility loci for esophageal squamous cell carcinoma (ESCC), the most common histological type of esophageal cancer, in the phospholipase C ε-1 gene (PLCE1). The aim of the present study was to investigate whether polymorphisms of PLCE1 were associated with the prognosis of ESCC patients in a high-incidence region of northern China. The PLCE1 rs2274223 A/G and rs11599672T/G single-nucleotide polymorphisms (SNPs) were genotyped by polymerase chain reaction-ligase detection reaction method in 207 ESCC patients with survival information. The mean age ± standard deviation of the 207 ESCC patients was 60.3±7.9 years. Sex, age, smoking status and family history of upper gastrointestinal cancer were not found to be associated with the survival time of ESCC patients. The mean survival time of rs2274223 SNP A/A, A/G and G/G genotype carriers were 42.9, 43.4 and 46.3 months, respectively; for rs11599672 SNP T/T, T/G and G/G genotype carriers the survival time were 42.8, 43.8 and 42.7 months, respectively. There was no significant difference in survival time among the ESCC patients with different genotypes of rs2274223 and rs11599672 SNPs. In conclusion, PLCE1 rs227423 and rs11599672 SNPs cannot be used as predictive markers for the survival of ESCC patients from a high-incidence region of northern China.

S100A14 rs11548103 G>A polymorphism is associated with a decreased risk of esophageal cancer in a Chinese population

Objective

In China in 2009, esophageal cancer was the fifth most commonly diagnosed malignancy and the fourth leading cause of malignancy-related death. Accumulating evidence indicates that genetic factors might play an important role in esophageal squamous cell carcinoma (ESCC) carcinogenesis.

Materials and Methods

In total, we recruited 629 ESCC patients and 686 controls. Genetic variations in the S100A14, MLH1, SMAD7 and CCL22/MDC genes were measured using the ligation detection reaction method.

Results

When the S100A14 rs11548103 GG genotype was considered as the reference group, the GA genotype associated with decreased risk of ESCC (GA vs. GG: adjusted OR = 0.73, 95% CI = 0.57–0.93, p = 0.009). In the dominant model, GA/AA variants were associated with a significantly decreased risk of ESCC compared with the GG genotype (GA/AA vs. GG: adjusted OR = 0.76, 95% CI = 0.61–0.95, p = 0.018). Logistic regression analyses showed that the MLH1 rs1800734 C>T, SMAD7 rs12953717 C>T and CCL22/MDC rs4359426C>A polymorphisms were not associated with the risk of ESCC in any of the models tested.

Conclusions

Our findings indicated that, in a Chinese population, rs11548103 might contribute to a decreased risk of ESCC. Further studies are need to confirm these data with results from a lager cohort and different ethnic origins.

Flap endonuclease-1 rs174538 G>A polymorphisms are associated with the risk of esophageal cancer in a Chinese population

BACKGROUND

Esophageal cancer has a high mortality rate, particularly in Asia, and there are obvious racial differences in regard to incidence. The purpose of our study was to assess the genetic susceptibility of functional single nucleotide polymorphisms in flap endonuclease-1 (FEN1) in esophageal squamous cell carcinoma ESCC.

METHODS

Clinical blood samples of 629 ESCC cases and 686 control samples were collected. The ligation detection reaction method was used to determine FEN 1 rs174538 G>A genotypes.

RESULTS

A significantly decreased risk of ESCC was associated with FEN1 rs174538 GA genotypes among patients under 63 years old.

CONCLUSIONS

Our results suggest that functional polymorphism FEN1 rs174538 G>A might affect personal susceptibility to ESCC. This result provides a solid theoretical foundation for further clinical study using larger sample sizes.

Two novel polymorphisms in PLCE1 are associated with the susceptibility to esophageal squamous cell carcinoma in Chinese population

Esophageal cancer is the sixth leading cause of cancer-associated death worldwide. Phospholipase C epsilon 1 (PLCE1) gene was found to be associated with the risk of esophageal squamous cell carcinoma (ESCC) by three large-scale genome-wide association studies (GWAS) in Chinese populations. To evaluate the association between the single nucleotide polymorphisms (SNPs) in PLCE1 gene and ESCC risk, a case-control study including 550 patients with ESCC and 550 age, gender-matched controls was carried out to investigate the genetic susceptibility of three SNPs (rs3765524 C/T and two unreported potentially functional SNPs rs10882379 G/A and rs829232 G/A) as well as the interactions of gene-gene and gene-environment in the development of ESCC. And the results showed that GA genotype of rs10882379 was significantly associated with reduced ESCC risk compared with GG genotype (adjusted OR [95% CI]: 0.66 [0.51, 0.86]), while AA genotype of rs829232 was significantly associated with increased ESCC risk compared with GG genotype (adjusted OR [95% CI]: 1.37 [1.12, 1.67]). The haplotype analysis showed increased ESCC risk in Grs10882379Crs3765524Ars829232 and Grs10882379Trs3765524Ars829232 haplotypes with OR (95% CI) of 1.40 (1.13, 1.73) and 1.66 (1.18, 2.34), respectively and inversely reduced ESCC risk in Ars10882379Crs3765524Grs829232 haplotype with OR (95% CI) of 0.74 (0.61, 0.91). The gene-environment interaction analysis emerged a best model consisted of four factors (rs10882379, rs3765524, rs829232 and family history of ESCC) that could increase the ESCC risk in the 'high risk group' with 4.45-fold (OR [95% CI]: 5.45 [4.13, 7.19]), compared to the 'low risk group.' Our results further validate that the SNPs in PLCE1 gene may contribute to the ESCC susceptibility in Chinese Han population. Also the gene-gene and gene-environment interactions play a certain crucial role in the ESCC progression.

Plasma Riboflavin Level is Associated with Risk, Relapse, and Survival of Esophageal Squamous Cell Carcinoma

Riboflavin is an essential micronutrient for normal cellular activity, and deficiency may result in disease, such as cancer. We performed a case-control study to explore the association of riboflavin levels with risk and prognosis of esophageal squamous cell carcinoma (ESCC). Plasma riboflavin levels, as measured by enzyme-linked immunosorbent assay (ELISA), in ESCC patients were significantly lower than in those of healthy controls (7.04 ± 6.34 ng/ml vs. 9.32 ± 12.40 ng/ml; P < 0.05). Moreover, there was an inverse relationship between riboflavin level and risk of ESCC (odds ratio (OR) = 0.97, 95% confidence interval (CI) = 0.95-0.99, P =  0.02). The 5-year relapse-free and overall survival rates were significantly lower when riboflavin levels were ≤0.8 ng/ml than >0.8 ng/ml (relapse-free survival rate: 29.4% vs. 54.8%; overall survival rate: 28.6% vs. 55.6%). Plasma riboflavin level was an independent protective factor for both relapse-free (hazard ratio (HR) = 0.325, 95% CI = 0.161-0.657, P = 0.002) and overall survival of ESCC patients (HR = 0.382, 95% CI = 0.190-0.768, P = 0.007). In conclusion, plasma riboflavin levels are significantly related to risk and prognosis of ESCC patients, suggesting that moderate supplementation of riboflavin will decrease risk and prevent recurrence of ESCC and also improve prognosis of ESCC patients.

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.

Single nucleotide polymorphism rs13042395 in the SLC52A3 gene as a biomarker for regional lymph node metastasis and relapse-free survival of esophageal squamous cell carcinoma patients

BACKGROUND

SLC52A3 was recently identified as a susceptibility gene for esophageal squamous cell carcinoma (ESCC). However, associations between the single nucleotide polymorphisms (SNPs) rs13042395 (C > T) and rs3746803 (G > A) in SLC52A3 and risk, tumor characteristics and survival of ESCC patients remain inconclusive and of unknown prognostic significance.

METHODS

Analyses of the association between SNPs in SLC52A3 and ESCC risk were performed on 479 ESCC cases, together with 479 controls, in a case-control study. Blood samples for cases and controls were collected and genotyped by real-time polymerase chain reaction (PCR) using TaqMan assays. Among the 479 ESCC cases, 343 cases with complete clinical data were used to investigate the association between SNPs and ESCC clinical characteristics; 288 cases with complete clinical data and 5-year follow-up data were used to analyze the association between SNPs and prognosis. Dual luciferase reporter assays and electrophoretic mobility shift assays (EMSAs) were used to investigate the biological function of rs13042395.

RESULTS

No association was found between SLC52A3 rs3746803 and susceptibility, tumor characteristics or survival of ESCC patients. For rs13042395, TT genotype carriers were likely to have reduced lymph node metastasis (odds ratio (OR) = 0.55, 95 % confidence interval (CI), 0.31-0.98) and longer relapse-free survival time (P = 0.03) . Also, both rs13042395 (hazard ratio (HR) = 0.62, 95 % CI, 0.38-0.99) and regional lymph node metastasis (HR = 2.06, 95 % CI, 1.36-3.13 for N1 vs. N0; HR = 2.88, 95 % CI, 1.70-4.86 for N2 vs. N0; HR = 2.08, 95 % CI, 1.01-4.30 for N3 vs. N0) were independent factors affecting relapse-free survival for ESCC patients who underwent surgery. Dual luciferase reporter assays and EMSAs suggested that the CC genotype of rs13042395 enhanced SLC52A3 expression, probably via binding with specific transcription factors.

CONCLUSIONS

The rs13042395 polymorphism in SLC52A3 is associated with regional lymph node metastasis and relapse-free survival in ESCC patients.

Evaluating the Association of Eight Polymorphisms with Cancer Susceptibility in a Han Chinese Population

Background

The identification of susceptibility genes for specific types of cancer can provide necessary information for the complete characterization of cancer syndromes. Eight single nucleotide polymorphisms (SNPs), rs465498, rs17728461, rs4488809, rs753955, rs13361707, rs9841504, rs2274223, and rs13042395, were reported by genome wide association studies (GWASs) to be closely related to the susceptibility of lung cancer (LC), gastric cancer (GC) or esophageal cancer (EC) in Han population from northern or southern China. However, Chinese Han people from different geographic areas may have different genetic backgrounds. This study aims to assess the genetic associations of the eight SNPs mentioned above with three cancers risk in a Han population from northwest China.

Methods

A total of 186 cancer-free controls and 436 cases with non-small cell lung cancer (NSCLC) (159 cases), non-cardia GC (167 cases) or EC (110 cases) were enrolled in this study. Chi-square test and polytomous logistic regression analyses were used to estimate the association between eight cancer-related SNPs and three cancers in a Han Chinese population from northwest China. The logistic regression results were adjusted for confounding factors and Benjamini and Hochberg False Discovery Rate (FDR) method was used to adjust the multiple hypothesis tests. Association analyses by cigarette smoking or alcohol drinking status were analyzed by crossover analyses.

Results

One of the eight SNPs, rs17728461 was associated with NSCLC susceptibility (in a heterozygous model, OR = 0.44, 95% CI = 0.27–0.72, p = 0.001). Two SNPs, rs753955 and rs13042395, were associated with the risk of non-cardia GC in different genetic models (p < 0.05). No SNPs were associated with EC. The crossover analyses showed that the rs13042395 CT genotype, combined with cigarette smoking or alcohol drinking, could further increase the risk for non-cardia GC (p < 0.05).

Conclusions

These results indicated that rs17728461 may be specifically associated with the risk of NSCLC. rs753955 and rs13042395 were specifically associated with susceptibility to non-cardia GC in Ningxia Han Chinese. Susceptibility-associated polymorphisms in the northwestern Han Chinese were not very consistent with those in the northern Han Chinese or southern Han Chinese. The validation of these findings with a functional evaluation and a larger population is still required.

Esophageal Squamous Cell Carcinoma and Gastric Cardia Adenocarcinoma Shared Susceptibility Locus in C20orf54: Evidence from Published Studies

This study aimed to determine whether C20orf54 rs13042395 polymorphism modify the risk of esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinomas (GCA) in common population. We conducted a systematic literature review and evaluated the quality of included studies based on Newcastle-Ottawa Scale (NOS). Pooled odds ratios (ORs) and corresponding 95% confidence intervals (95%CIs) were calculated to estimate the strengths of the associations. 9 articles (10 studies) were identified for synthesis analyses. Overall, the results indicated that the C20orf54 rs13042395 genotype was subtly decrease the risk of ESCC (T vs. C: OR = 0.95; 95%CI = 0.90–0.99; P = 0.02) and the rs13042395 polymorphism was associated with a decreased risk of GCA (T vs. C: OR = 0.95; 95%CI = 0.91–0.98; P < 0.01). The subsets were divided by smoking and drinking status, but none of the genetic comparisons reached statistical significance. Subgroup analysis was also stratified by body mass index (BMI), rs13042395 polymorphism was significantly associated with a subtly decreased cancer risk in under-weight group and normal group, but no association was observed in over-weight group. In conclusion, C20orf54 rs13042395 polymorphism was significantly associated with decreased ESCC and GCA risk especially for the subjects with under-weight or normal.

PLCε signaling in cancer

PURPOSE

As one of the members of the PLC family, the phosphoinositide-specific phospholipase Cε (PLCε) has been shown to play pivotal roles in multiple signal pathways and control a variety of cellular functions. A number of studies have shown that aberrant regulation of PLCε was involved in various types of animal and human cancer. However, the role of PLCε in cancer remains elusive. In this review, we provide an overview of the PLCε, especially its roles in multiple signal pathways, and summarize the recent findings that highlight the roles of PLCε in carcinogenesis and cancer progression, making an avenue to provide a novel therapeutic strategy for the treatment of cancer.

METHODS

A literature search mainly paying attention to the network of PLCε involved in tumorigenesis and development was performed in electronic databases.

RESULTS

PLCε plays a key role in medicating the development and progression of human cancers with highest potency to be a target of cancer prevention and treatment.

Association of colorectal cancer susceptibility variants with esophageal cancer in a Chinese population

AIM: To investigate the association between colorectal cancer (CRC) genetic susceptibility variants and esophageal cancer in a Chinese Han population.

METHODS: A case-control study was conducted including 360 esophageal cancer patients and 310 healthy controls. Thirty-one single-nucleotide polymorphisms (SNPs) associated with CRC risk from previous genome-wide association studies were analyzed. SNPs were genotyped using Sequenom Mass-ARRAY technology, and genotypic frequencies in controls were tested for departure from Hardy-Weinberg equilibrium using a Fisher’s exact test. The allelic frequencies were compared between cases and controls using a χ² test. Associations between the SNPs and the risk of esophageal cancer were tested using various genetic models (codominant, dominant, recessive, overdominant, and additive). ORs and 95%CIs were calculated by unconditional logistic regression with adjustments for age and sex.

RESULTS: The minor alleles of rs1321311 and rs4444235 were associated with a 1.53-fold (95%CI: 1.15-2.06; P = 0.004) and 1.28-fold (95%CI: 1.03-1.60; P = 0.028) increased risk of esophageal cancer in the allelic model analysis, respectively. In the genetic model analysis, the C/C genotype of rs3802842 was associated with a reduced risk of esophageal cancer in the codominant model (OR = 0.52, 95%CI: 0.31-0.88; P = 0.033) and recessive model (OR = 0.55, 95%CI: 0.34-0.87; P = 0.010). The rs4939827 C/T-T/T genotype was associated with a 0.67-fold (95%CI: 0.46-0.98; P = 0.038) decreased esophageal cancer risk under the dominant model. In addition, rs6687758, rs1321311, and rs4444235 were associated with an increased risk. In particular, the T/T genotype of rs1321311 was associated with an 8.06-fold (95%CI: 1.96-33.07; P = 0.004) increased risk in the codominant model.

CONCLUSION: These results provide evidence that known genetic variants associated with CRC risk confer risk for esophageal cancer, and may bring risk for other digestive system tumors.

Variant TP53BP1 rs560191 G>C is associated with risk of gastric cardia adenocarcinoma in a Chinese Han population

OBJECTIVE

To investigate the association between gastric cardia adenocarcinoma (GCA) and ten functional single nucleotide polymorphisms (SNPs), including TP53BP1 rs560191 G>C, CASP8 rs1035142 G>T, CASP7 rs3127075 G>C, CASP7 rs7907519 C>A, and six C1orf10/CRNN variants. We performed a hospital-based case-control study to evaluate the genetic effects of these SNPs.

METHODS

Two hundred and forty-three GCA cases and 476 controls were enrolled in this study. A custom-by-design 48-Plex SNPscan(TM) Kit was used to determine their genotypes.

RESULTS

When the TP53BP1 rs560191 GG homozygote genotype was used as the reference group, the GC genotype was associated with a significantly increased risk of GCA. The CC genotype was not associated with the risk of GCA compared with the GG genotype. None of the CASP8 rs1035142 G>T, CASP7 rs3127075 G>C, CASP7 rs7907519 C>A or the six C1orf10/CRNN polymorphisms showed a significant difference in genotype distributions between the cases and the controls.

CONCLUSIONS

The results demonstrated that the functional polymorphism TP53BP1 rs560191 G>C might contribute to GCA susceptibility. However, the statistical power of our study was limited. Large, well-designed studies and further functional investigations are needed to confirm our findings.

Interleukin 12B rs3212227 T > G polymorphism was associated with an increased risk of gastric cardiac adenocarcinoma in a Chinese population

Gastric cardiac adenocarcinoma (GCA) is one of common malignant tumors in the world. Multiple genes that play critical roles in inflammatory pathways probably are associated with GCA risk. We conducted a hospital-based case-control study to evaluate the genetic effects of functional single nucleotide polymorphisms (SNPs): interleukin 9 (IL9) rs31563 C > T, IL9 rs31564 G > T, IL10 rs1800872 T > G, IL12A rs2243115 T > G, IL12B rs3212227 T > G, and IL13 rs1800925 C > T on the development of GCA. Two hundred and forty-three GCA cases and 476 controls were recruited. Their genotypes were determined using a custom-by-design 48-Plex SNPscan kit. IL12B rs3212227 T > G polymorphism was associated with the increased risk of GCA. However, there was no significant association between the other five SNPs and GCA risk. Stratified analyses indicated that the risk of GCA associated with the IL12B rs3212227 T > G polymorphism was evident among female patients and patients who never smoked or consumed alcoholic drinks. These findings indicated that functional polymorphism IL12B rs3212227 T > G might correlate with GCA risk. However, our results were obtained with a limited sample size; the power of our analysis was low. Larger studies are required to confirm the current findings.

Long noncoding RNAs POLR2E rs3787016 C/T and HULC rs7763881 A/C polymorphisms are associated with decreased risk of esophageal cancer

Worldwide, rates of esophageal cancer have been keeping highly in recent decades. Genetic variants in multiple cellular pathways might play an important role in altering risk of esophageal carcinoma. In this study, long noncoding RNAs (lncRNAs) functional single nucleotide polymorphisms (SNPs) were investigated in Chinese Han populations. We have genotyped the ANRIL rs2151280 T/C, POLR2E rs3787016 C/T, and HULC rs7763881 A/C SNPs in 380 esophageal squamous cell carcinoma (ESCC) cases and 380 cancer-free controls. POLR2E rs3787016 C/T was associated with a significantly decreased risk for ESCC (CT vs. CC: OR 0.62, 95 % CI 0.44-0.87, P = 0.005; adjusted OR 0.62, 95 % CI 0.44-0.87, P = 0.005). The other SNP, HULC rs7763881, also showed a suggestive association (AC vs. AA: OR 0.70, 95 % CI 0.50-0.98, P = 0.037; adjusted OR 0.69, 95 % CI 0.49-0.97, P = 0.031). ANRIL rs2151280 T/C SNP was not associated with risk of ESCC. In the future, larger studies with other ethnic populations, tissue-specific biological characterization, and detailed individual information should be undertaken to validate current findings.

Associations of genetic variants in the PSCA, MUC1 and PLCE1 genes with stomach cancer susceptibility in a Chinese population

BACKGROUND

Several genetic variants including PSCA rs2294008 C>T and rs2976392 G>A, MUC1 rs4072037 T>C, and PLCE1 rs2274223 A>G have shown significant association with stomach cancer risk in the previous genome-wide association studies (GWASs).

METHODS

To evaluate associations of these SNPs in the Han Chinese, an independent hospital based case-control study was performed by genotyping these four polymorphisms in a total of 692 stomach cancer cases and 774 healthy controls acquired by using frequency matching for age and gender. False-positive report probability (FPRP) analysis was also performed to validate all statistically significant findings.

RESULTS

In the current study, significant association with stomach cancer susceptibility was observed for all the four polymorphisms of interest. Specifically, a significant increased stomach cancer risk was associated with PSCA rs2294008 (CT vs. CC: adjusted OR = 1.37, 95% CI = 1.07-1.74, and CT/TT vs.CC: adjusted OR = 1.30, 95% CI = 1.03-1.63), PSCA rs2976392 (AG vs. GG: adjusted OR = 1.30, 95% CI = 1.02-1.65, and AG/AA vs. GG: adjusted OR = 1.26, 95% CI = 1.00-1.59), or PLCE1 rs2274223 (AG vs. AA: adjusted OR = 1.48, 95% CI = 1.15-1.90, and AG/GG vs. AA: adjusted OR = 1.45, 95% CI = 1.14-1.84), respectively. In contrast, MUC1 rs4072037 was shown to decrease the cancer risk (CT vs. TT: adjusted OR = 0.77, 95% CI = 0.60-0.98). Patients with more than one risk genotypes had significant increased risk to develop stomach cancer (adjusted OR = 1.30, 95% CI = 1.03-1.64), when compared with those having 0-1 risk genotypes. Stratified analysis indicated that the increased risk was more pronounced in younger subjects, men, ever smokers, smokers with pack years ≤ 27, patients with high BMI, or non-cardia stomach cancer.

CONCLUSIONS

This study substantiated the associations between four previous reported genetic variants and stomach cancer susceptibility in an independent Han Chinese population. Further studies with larger sample size and different ethnicities are warranted to validate our findings.

Association between PLCE1 rs2274223 A > G polymorphism and cancer risk: proof from a meta-analysis

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.

MUTYH association with esophageal adenocarcinoma in a Han Chinese population

Adenocarcinoma of esophagus (AE) is a complex disease, affected by a variety of genetic and environmental factors. Much evidence has shown that the MutY glycosylase homologue (MUTYH) plays a key role in the pathogenesis of many cancers. However, there have been no reports on influence on AE in the Han Chinese population. The objective of this study was to investigate this issue. A gene-based association study was conducted using three single nucleotide polymorphisms(SNPs) reported in previous studies. The three SNPs (rs3219463, rs3219472, rs3219489) were genotyped in 207 unrelated AE patients and 249 healthy controls in a case-control study using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). The results revealed that the genotype distribution of rs3219472 differed between the case and control groups (OR=1.66,95%CI=1.11-2.48, P=0.012 ), indicating that an association may exist between MUTYH and AE. These findings support a signifcant role for MUTYH in AE pathogenesis in the Han Chinese population.

Role of novel and GWAS originated PLCE1 genetic variants in susceptibility and prognosis of esophageal cancer patients in northern Indian population

Recent genome-wide association studies (GWAS) have identified variants in phospholipase C epsilon1 (PLCE1) as novel susceptibility markers for esophageal squamous cell carcinoma (ESCC) in Chinese population. Although few studies have replicated this findings in other populations, but results are contradictory. So, we aimed to replicate association of two previously reported non-synonymous polymorphisms (rs2274223A>G and rs3765524C>T) from haplotype block 10 and evaluated a novel variant (rs7922612C>T) from haplotype block 2 of PLCE1 with susceptibility and prognosis of ESCC in northern Indian population. The genotyping of PLCE1 variants were performed in 293 histopathologically confirmed incident ESCC cases (including 177 follow-up cases) and 314 age-, gender-, and ethnicity-matched controls using PCR RFLP. All statistical analyses were performed through SPSS version 15.0. Modeling and functional prediction of two non-synonymous variants were carried out using bioinformatics tools. PLCE1 polymorphisms were not associated with susceptibility to ESCC or its clinical phenotypes (tumor location/lymph node metastasis). No interaction with environmental risk factors was found. In silico analysis suggested negligible effect on structure of PLCE1 protein due to PLCE1 rs2274223 (H1927R) and rs3765524 (T1777I) polymorphisms. Survival analysis showed PLCE1 rs7922612CT + TT genotype conferred adverse outcome to ESCC patients. Our study for the first time suggests that GWAS originated PLCE1 variants do not have independent role in susceptibility of ESCC in northern Indian population; however, a novel haplo-tagging SNP rs7922612 may modify survival outcome of ESCC patients.

TERT-CLPTM1L Rs401681 C>T polymorphism was associated with a decreased risk of esophageal cancer in a Chinese population

Background

Esophageal cancer was the fifth most commonly diagnosed cancer and the fourth leading cause of cancer-related death in China in 2009. Esophageal squamous cell carcinoma (ESCC) accounts for more than 90 percent of esophageal cancers. Genetic factors probably play an important role in the ESCC carcinogenesis.

Methods

We conducted a hospital based case-control study to evaluate functional hTERT rs2736098 G>A and TERT-CLPTM1L rs401681 C>T single nucleotide polymorphisms (SNPs) on the risk of ESCC. Six hundred and twenty-nine ESCC cases and 686 controls were recruited. Their genotypes were determined using the ligation detection reaction (LDR) method.

Results

When the TERT-CLPTM1L rs401681 CC homozygote genotype was used as the reference group, the CT genotype was associated with a significantly decreased risk of ESCC (adjusted OR  = 0.74, 95% CI  = 0.58–0.94, p = 0.012); the CT/TT variants were associated with a 26% decreased risk of ESCC (adjusted OR  = 0.74, 95% CI  = 0.59–0.93, P = 0.009). The significantly decreased risk of ESCC associated with the TERT-CLPTM1L rs401681 C>T polymorphism was associated with male sex, young age (<63 years in our study) and alcohol consumption. No association between the hTERT rs2736098 G>A polymorphism and ESCC risk was observed.

Conclusion

TERT-CLPTM1L rs401681 CT and CT/TT genotypes were associated with decreased risk of ESCC, particularly among men, young patients and those reported to be drinkers. However, our results are preliminary conclusions. Larger studies with more rigorous study designs are required to confirm the current findings.

p21 rs3176352 G>C and p73 rs1801173 C>T polymorphisms are associated with an increased risk of esophageal cancer in a Chinese population

Objective

Esophageal cancer was the fifth most commonly diagnosed cancer and the fourth leading cause of cancer-related death in China in 2009. Genetic factors might play an important role in esophageal squamous cell carcinoma (ESCC) carcinogenesis.

Designs and Methods

To evaluate the effect p21, p53, TP53BP1 and p73 single nucleotide polymorphisms (SNPs) on the risk of ESCC, we conducted a hospital based case–control study. A total of 629 ESCC cases and 686 controls were recruited. Their genotypes were determined using ligation detection reaction (LDR) method.

Results

When the p21 rs3176352 GG homozygote genotype was used as the reference group, the CC genotype was associated with a significantly increased risk of ESCC. When the p73 rs1801173 CC homozygote genotype was used as the reference group, the CT genotype was associated with a significantly increased risk of ESCC. After Bonferroni correction, for p21 rs3176352 G>C, the p_correct was still significant. For the other six SNPs, in all comparison models, no association between the polymorphisms and ESCC risk was observed.

Conclusions

p21 rs3176352 G>C and p73 rs1801173 C>T SNPs are associated with increased risk of ESCC. To confirm the current findings, additional, larger studies and tissue-specific biological characterization are required.

PLCE1 rs2274223 polymorphism contributes to risk of esophageal cancer: evidence based on a meta-analysis

We sought to reassess the association of PLCE1 rs2274223 and susceptibility to esophageal cancer (EC) through a meta-analysis of published case-control studies. Using the PubMed and Embase, we identified nine articles including fourteen case-control studies (15,225 cases and 23,620 controls). ORs and 95 % confidence intervals (CIs) of GG vs. AA, GG + GA vs. AA, GG vs. GA + AA, G vs. A, and AG vs. AA genetic models were estimated for each study. All of the genetic models indicated a statistically significant positive association with EC risk. The association appeared most pronounced for carriers of GG genotype (GG vs. AA: OR, 1.35; 95 % CI, 1.17 to 1.57), and weakest for individuals carrying GA genotype (GA vs. AA: OR, 1.13; 95 % CI, 1.05 to 1.23). Stratification analyses showed similar results in the population of Asians and in esophageal squamous cell carcinoma (ESCC). This meta-analysis provides strong statistical evidence for an elevated risk of EC associated with PLCE1 rs2274223. The association remains significant in Asian population and ESCC. Further investigations are warranted to validate these findings.

PLCE1 rs2274223 A>G polymorphism and cancer risk: a meta-analysis

Phospholipase C epsilon 1 gene (PLCE1) encodes a phospholipase enzyme which regulates various physiological processes (cell growth, differentiation, and apoptosis) and is supposed to play a critical role in carcinogenesis. Recently, a single nucleotide polymorphism (rs2274223 A>G) in PLCE1 was reported as a novel susceptibility locus for esophageal and gastric cancers by genome-wide association studies performed in Chinese population. However, individual association studies replicating this finding showed inconclusive results. Therefore, we performed a meta-analysis of eligible studies to derive precise estimation of the association of PLCE1 rs2274223 A>G polymorphism with cancer risk. We performed pooled analysis of 12 case–control studies including 7,622 cases and 9,555 controls. Odds ratios and 95 % confidence interval were calculated to assess strength of association in overall studies and in subgroup analysis stratified by ethnicity, cancer types, and source of controls. All statistical analyses were performed by MIX 2.0 software. We found that PLCE1 rs2274223 A>G polymorphism was significantly associated with increased risk of cancer in log additive/dominant model and at allele level (GG vs. AA: OR = 1.24, 95 % CI = 1.01–1.53, P = 0.039; AG vs. AA: OR = 1.24, 95 % CI = 1.16–1.32, P < 0.001; AG + GG vs. AA: OR = 1.22, 95 % CI = 1.12–1.34, P < 0.001; and G vs. A allele: OR = 1.15, 95 % CI = 1.05–1.25, P = 0.002). Further, stratified analysis showed elevated risk of only gastric and esophageal tumors. Sub-group analysis based on ethnicity suggests PLCE1 polymorphism conferred significant risk among Asian (Chinese) but not in Caucasian. In conclusion, PLCE1 rs2274223 polymorphism may be used as potential biomarker for cancer susceptibility particularly for esophageal/gastric cancer and for the Chinese population.

Interleukin 10 rs1800872 T>G polymorphism was associated with an increased risk of esophageal cancer in a Chinese population

AIM

Esophageal cancer is the eighth most common cancer and sixth leading cause of cancer associated death worldwide. The 5 year survival rate for esophageal cancer patients is very poor and accounts for only 12.3%. Besides environmental risk factors, genetic factors might play an important role in the esophageal cancer carcinogenesis.

METHODS

We conducted a hospital based case-control study to evaluate the genetic effects of functional single nucleotide polymorphisms (SNPs): interleukin 9 (IL9) rs31563 C>T, IL9 rs31564 G>T, IL10 rs1800872 T>G, IL12A rs2243115 T>G, IL12B rs3212227 T>G and IL13 rs1800925 C>T on the development of esophageal cancer. A total of 380 esophageal squamous cell carcinoma (ESCC) cases and 380 controls were recruited for this study. The genotypes were determined using a custom-by-design 48-Plex SNPscanTM Kit.

RESULTS

The IL10 rs1800872 T>G polymorphism was associated with an increased risk of ESCC. However, there were no significant links with the other five SNPs. Stratified analyses indicated no significant risk of ESCC associated with the IL10 rs1800872 T>G polymorphism evident among any subgroups.

CONCLUSION

These findings indicated that functional polymorphism IL10 rs1800872 T>G might contribute to ESCC susceptibility. However, our results were obtained with a limited sample size, so that the power of our analysis was low. Future larger studies with more rigorous study designs of other ethnic populations are required to confirm the current findings.

N-acetyltransferase 2 polymorphisms and risk of esophageal cancer in a Chinese population

Esophageal cancer was the fifth most commonly diagnosed cancer and the fourth leading cause of cancer-related death in China in 2009. Genetic factors might play an important role in the carcinogenesis of esophageal squamous cell carcinoma (ESCC). We conducted a hospital-based case-control study to evaluate ten NAT2 tagging single nucleotide polymorphisms (SNPs) on the risk of ESCC. Six hundred and twenty-nine ESCC cases and 686 controls were recruited. Their genotypes were determined using the ligation detection reaction method. In the single locus analyses, there was a borderline statistically significant difference in genotype frequencies of NAT2 rs1565684 T>C SNP between the cases and the controls (p = 0.057). The NAT2 rs1565684 CC genotype was associated with a borderline significantly increased risk for ESCC (CC vs. TT: adjusted OR = 1.77, 95% CI = 0.97–3.21, p = 0.063 and CC vs. TT/TC: adjusted OR = 1.68, 95% CI = 0.93–3.04, p = 0.085). The association was evident among older patients and patients who never drunk. After the Bonferroni correction, in all comparison models, NAT2 rs1565684 T>C SNP was not associated with ESCC risk (p>0.05). For the other nine NAT2 SNPs, after Bonferroni correction, in all comparison models, the nine SNPs were also not associated with ESCC risk (p>0.05). Thus, nine NAT2 tagging SNPs were not associated with risk of ESCC. NAT2 rs1565684 T>C SNP might play a slight role in ESCC etiology. Additional, larger studies and tissue-specific biological characterization are required to confirm the current findings.

Association between phospholipase C epsilon gene (PLCE1) polymorphism and colorectal cancer risk in a Chinese population

OBJECTIVE

To investigate the association between a single nucleotide polymorphism rs2274223 (adenine [A] to guanine [G]) in the phospholipase C epsilon 1 (PLCE1) gene and susceptibility to colorectal cancer (CRC).

METHODS

The PLCE1 rs2274223 polymorphism was genotyped in patients with CRC and age- and sex-matched cancer-free control subjects from a Chinese population in a case-control study. PLCE1 mRNA levels in pair-matched tumour and adjacent noncancerous tissue were evaluated by real-time quantitative reverse transcription-polymerase chain reaction.

RESULTS

A total of 417 patients with CRC and 416 control subjects were enrolled in the study. The AG and GG genotypes of PLCE1 rs2274223 were associated with a significantly increased risk of CRC (for AG + GG versus AA: adjusted odds ratio 1.52, 95% confidence interval 1.15, 2.00). PLCE1 mRNA levels were significantly lower in tumours than in adjacent noncancerous tissue. Lower levels of PLCE1 mRNA were observed in both AG and GG genotype carriers compared with the AA genotype carriers.

CONCLUSIONS

These results indicate that the PLCE1 rs2274223 A > G change might reduce gene expression and that the variant G genotype might contribute to the increased risk of CRC.

MTHFR rs1801133 C>T polymorphism is associated with an increased risk of tetralogy of Fallot

Abnormal folate metabolism and common variants of folate-metabolizing enzymes have been described as possible risk factors for congenital heart disease (CHD). Two important folate-metabolizing enzymes involved in the folate/homocysteine metabolic pathway are 5,10-methylenetetrahydrofolate reductase (MTHFR) and methylenetetrahydrofolate dehydrogenase 1 (MTHFD1). MTHFR and MTHFD1 polymorphisms may be associated with CHD susceptibility. To evaluate the impact of MTHFR and MTHFD1 single-nucleotide polymorphisms (SNPs) on CHD susceptibility, we genotyped functional MTHFR SNPs rs1801133 C>T, rs1801131 A>C and rs2274976 G>A, and MTHFD SNPs rs2236225 C>T, rs1950902 G>A and rs1076991 A>G in a hospital-based case-control study of 173 tetralogy of Fallot (TOF) cases and 207 non-CHD controls. When MTHFR rs1801133 CC homozygote genotype was used as the reference group, the TT genotype was associated with a significantly increased risk for TOF [TT vs. CC: odds ratio (OR)=1.67; 95% confidence interval (CI): 1.01-2.75; P=0.046]. In the recessive model, when MTHFR rs1801133 CC/CT genotype was used as the reference group, the TT homozygote genotype was associated with a significantly increased risk for TOF (OR=1.81, 95% CI: 1.15-2.84; P=0.010). In conclusion, our findings suggest that MTHFR rs1801133 C>T polymorphism may play a role in susceptibility for TOF. Large-scale studies with a more rigorous study design including diverse ethnic populations are required to confirm these findings.

Common genetic variants at 1q22 and 10q23 and gastric cancer susceptibility in a Korean population

Genetic variants at 1q22 and 10q23 were identified as genetic markers of both gastric cancer and esophageal squamous cell carcinoma susceptibility by two genome-wide association studies. The aim of this study was to determine whether rs4072037A > G in MUC1 at 1q22 and rs2274223A > G in PLCE1 at 10q23 are associated with a risk of gastric cancer in a Korean population. We conducted a large-scale case-control study of 3,245 patients with gastric cancer and 1,700 controls. The allele frequencies of rs4072037G and rs2274223G were 11.2 and 25.5% among patients with gastric cancer, compared with 12.8 and 26.4%, respectively, among controls. We found that the rs4072037 AG genotype was significantly associated with a reduced risk of gastric cancer [odds ratios (OR) = 0.78; 95% confidence interval (CI) = 0.67-0.91 for AG vs AA]. Compared with the rs2274223 AA genotype, we found a significant association between the rs2274223 AG genotype and a weakly reduced risk of gastric cancer (OR = 0.87; 95% CI = 0.76-0.99 for AG vs AA). Our data suggest that genetic variants at 1q22 and 10q23 play a role in gastric carcinogenesis.

Hsa-miR-34b/c rs4938723 T>C and hsa-miR-423 rs6505162 C>A polymorphisms are associated with the risk of esophageal cancer in a Chinese population

Esophageal cancer is the eighth most common cancer and sixth leading cause of cancer associated death worldwide. Besides environmental risk factors, genetic factors might play an important role in the esophageal cancer carcinogenesis. We conducted a hospital based case–control study to evaluate the genetic susceptibility of functional single nucleotide polymorphisms (SNPs) in the microRNAs on the development of esophageal cancer. A total of 629 esophageal squamous cell carcinoma (ESCC) cases and 686 controls were recruited for this study. The hsa-miR-34b/c rs4938723 T>C, pri-miR-124-1 rs531564 C>G, pre-miR-125a rs12975333 G>T and hsa-miR-423 rs6505162 C>A genotypes were determined using Ligation Detection Reaction (LDR) method. Our results demonstrated that hsa-miR-34b/c rs4938723 CC genotype had a decreased risk of ESCC. The association was evident among patients who never drinking. Hsa-miR-423 rs6505162 C>A might associated with a significantly increased risk of ESCC in patients who smoking. These findings indicated that functional polymorphisms hsa-miR-34b/c rs4938723 T>C and hsa-miR-423 rs6505162 C>A might alter individual susceptibility to ESCC. However, our results were obtained with a limited sample size. Future larger studies with other ethnic populations are required to confirm current findings.

Gastric cancer-molecular and clinical dimensions

Gastric cancer imposes a considerable health burden around the globe despite its declining incidence. The disease is often diagnosed in advanced stages and is associated with a poor prognosis for patients. An in-depth understanding of the molecular underpinnings of gastric cancer has lagged behind many other cancers of similar incidence and morbidity, owing to our limited knowledge of germline susceptibility traits for risk and somatic drivers of progression (to identify novel therapeutic targets). A few germline (PLCE1) and somatic (ERBB2, ERBB3, PTEN, PI3K/AKT/mTOR, FGF, TP53, CDH1 and MET) alterations are emerging and some are being pursued clinically. Novel somatic gene targets (ARID1A, FAT4, MLL and KMT2C) have also been identified and are of interest. Variations in the therapeutic approaches dependent on geographical region are evident for localized gastric cancer-differences that are driven by preferences for the adjuvant strategies and the extent of surgery coupled with philosophical divides. However, greater uniformity in approach has been noted in the metastatic cancer setting, an incurable condition. Having realized only modest successes, momentum is building for carrying out more phase III comparative trials, with some using biomarker-based patient selection strategies. Overall, rapid progress in biotechnology is improving our molecular understanding and can help with new drug discovery. The future prospects are excellent for defining biomarker-based subsets of patients and application of specific therapeutics. However, many challenges remain to be tackled. Here, we review representative molecular and clinical dimensions of gastric cancer.

Heterozygote of PLCE1 rs2274223 increases susceptibility to human papillomavirus infection in patients with esophageal carcinoma among the Kazakh populations

The involvement of human papillomavirus (HPV) in the carcinogenesis of esophageal squamous carcinoma remains undetermined. However, three genome-wide association studies of esophageal cancer have identified a shared susceptibility locus at 10q23 (rs2274223: A5780G) in phospholipase C epsilon 1 (PLCE1). The current study aims to present a comprehensive and novel spectrum about the HPV genotype distribution of esophageal carcinoma in Kazakhs and assess its association with PLCE1 polymorphisms. The HPV genotypes in 183 patients with esophageal cancer and 89 controls selected from the Kazakh population were evaluated using the HPV gene chip. The PLCE1 rs2274223 variant was genotyped in esophageal carcinoma patients by MALDI-ToF Mass Spectrometry. The presence of seven HPV genotypes in esophageal carcinoma tissues-including HPV 16, 18, 35, 52, 6, 11, 43-was significantly higher at 31.7% than those in controls at 9.0% (P < 0.001). Such presence was strongly associated with increased risk of esophageal carcinoma (OR 4.70; 95% CI 2.13-10.36). Among all HPV genotypes detected, HPV16 was the most common genotype identified (29.0%, OR 4.13; 95% CI 1.87-9.13), which is significantly associated with well-differentiated esophageal carcinoma (P = 0.037). HPV-positive patients were generally younger than HPV-negative patients (70.1% vs. 29.3%, P = 0.013). PLCE1 rs2274223 genotypes AG and AG/GG were significantly associated with HPV-positive patients with esophageal carcinoma (OR 2.05, 95% CI 1.03-4.08 and OR 1.98, 95% CI 1.02-3.84, respectively). These findings suggest that heterozygote of PLCE1 rs2274223 increases susceptibility to HPV infection in patients with esophageal carcinoma among the Kazakh populations.

Increased risk of developing digestive tract cancer in subjects carrying the PLCE1 rs2274223 A>G polymorphism: evidence from a meta-analysis

Background

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.

Methods

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.

Results

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.

Conclusion

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.

Gastric cancer-molecular and clinical dimensions

Gastric cancer imposes a considerable health burden around the globe despite its declining incidence. The disease is often diagnosed in advanced stages and is associated with a poor prognosis for patients. An in-depth understanding of the molecular underpinnings of gastric cancer has lagged behind many other cancers of similar incidence and morbidity, owing to our limited knowledge of germline susceptibility traits for risk and somatic drivers of progression (to identify novel therapeutic targets). A few germline (PLCE1) and somatic (ERBB2, ERBB3, PTEN, PI3K/AKT/mTOR, FGF, TP53, CDH1 and MET) alterations are emerging and some are being pursued clinically. Novel somatic gene targets (ARID1A, FAT4, MLL and KMT2C) have also been identified and are of interest. Variations in the therapeutic approaches dependent on geographical region are evident for localized gastric cancer-differences that are driven by preferences for the adjuvant strategies and the extent of surgery coupled with philosophical divides. However, greater uniformity in approach has been noted in the metastatic cancer setting, an incurable condition. Having realized only modest successes, momentum is building for carrying out more phase III comparative trials, with some using biomarker-based patient selection strategies. Overall, rapid progress in biotechnology is improving our molecular understanding and can help with new drug discovery. The future prospects are excellent for defining biomarker-based subsets of patients and application of specific therapeutics. However, many challenges remain to be tackled. Here, we review representative molecular and clinical dimensions of gastric cancer.

A genetic polymorphism in lincRNA-uc003opf.1 is associated with susceptibility to esophageal squamous cell carcinoma in Chinese populations

The development of esophageal squamous cell carcinoma (ESCC) is a multifactorial process, and associations between genetic variants and ESCC have been identified in genome-wide association studies. The aim of this study was to evaluate the effects of single nucleotide polymorphisms (SNPs) of long intergenic non-coding RNAs (lincRNAs) on ESCC susceptibility in Chinese populations. We scoured exons of lincRNAs located in ESCC susceptibility loci for all probable functional SNPs. These 52 SNPs were opted for and genotyped in 1493 ESCC patients and 1553 cancer-free controls from eastern and southern Chinese populations, and their associations with the risk for ESCC were estimated using logistic regression. Functional relevance was further examined by biochemical assays. Significant differences were found between patients and controls in the genotype frequencies for the rs11752942A>G site in the lincRNA-uc003opf.1 exon. Compared with the rs11752942AA genotype, AG and GG genotypes had a significantly reduced risk of ESCC (adjusted odds ratio = 0.73; 95% confidence interval = 0.63-0.84). Biochemical analysis demonstrated that, when compared with the A allele, the rs11752942G allele could markedly attenuate the level of lincRNA-uc003opf.1 both in vivo and in vitro by binding micro-RNA-149*, thereby affecting cell proliferation and tumor growth. These findings indicated that functional polymorphism rs11752942A>G in lincRNA-uc003opf.1 exon might be a genetic modifier for the development of ESCC.