Genetic heterogeneity of oesophageal cancer in high-incidence areas of southern and northern China

FOXK1 regulates malignant progression and radiosensitivity through direct transcriptional activation of CDC25A and CDK4 in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a serious malignancy with poor prognosis, necessitating identification of oncogenic mechanisms for novel therapeutic strategies. Recent studies have highlighted the significance of the transcription factor forkhead box K1 (FOXK1) in diverse biological processes and carcinogenesis of multiple malignancies, including ESCC. However, the molecular pathways underlying FOXK1's role in ESCC progression are not fully understood, and its potential role in radiosensitivity remains unclear. Here, we aimed to elucidate the function of FOXK1 in ESCC and explore the underlying mechanisms. Elevated FOXK1 expression levels were found in ESCC cells and tissues, positively correlated with TNM stage, invasion depth, and lymph node metastasis. FOXK1 markedly enhanced the proliferative, migratory and invasive capacities of ESCC cells. Furthermore, silencing FOXK1 resulted in heightened radiosensitivity by impeding DNA damage repair, inducing G1 arrest, and promoting apoptosis. Subsequent studies demonstrated that FOXK1 directly bound to the promoter regions of CDC25A and CDK4, thereby activating their transcription in ESCC cells. Moreover, the biological effects mediated by FOXK1 overexpression could be reversed by knockdown of either CDC25A or CDK4. Collectively, FOXK1, along with its downstream target genes CDC25A and CDK4, may serve as a promising set of therapeutic and radiosensitizing targets for ESCC.

Familial Esophageal Cancer in Taihang Mountain, China: An Era of Personalized Medicine Based on Family and Population Perspective

In the Taihang Mountain areas, known as the “esophageal cancer zone” in China, the incidence of esophageal cancer (ESCA) ranks the first in the country and shows a familial and regional clustering trend. Taihang Mountain areas are located in a mountainous area, with inconvenient transportation, limited living conditions, unbalanced diet, and poor nutrition. Ninety percent of the pathological types of ESCA in Taihang Mountain areas are squamous cell carcinoma, among which the risk factors have not been well understood. These areas are usually remote villages and mountains with low population mobility, large family members, similar environmental factors, and a clear and stable genetic background. Therefore, according to the current situation, second-generation sequencing and multigroup analysis technology are used to analyze the familial ESCA patients; disease-related genetic variation are located; and then disease-related susceptibility genes associated with ESCA are screened and analyzed. Health education, tobacco control, endoscopic screening, and other health management projects for suspected and high-risk patients in areas with a high incidence of ESCA can be carried out for screening and early diagnosis, and the incidence of ESCA in Taihang Mountain areas can be reduced. A comprehensive continuous care pattern based on traditional medical nursing to track, monitor, evaluate, and intervene with patients diagnosed with ESCA to facilitate them with medications guidance, dietary guidance, and timely health problem-solving is established. Furthermore, statistical analysis of epidemiology, gene sequencing, and family genetics information can be performed on patients with ESCA in the Taihang Mountains areas to clarify the relationship between genetic phenotype and genotype during the occurrence of ESCA.

Awareness for Endoscopic Screening Among Accompanying Children of Hospitalized Esophageal Cancer Patients in Henan

The free generalized endoscopic screening for diagnosis of early esophageal cancer and precancerous lesion could not be satisfactorily implemented in China. At present, the decision to accept endoscopic screening at their own expense may largely depend on the public awareness. This study was aimed to investigate the awareness and other influencing factors associated with the accompanying children of esophageal cancer patients after their hospitalization. In this cross-sectional study, from April to June 2016, 233 children of accompanying patients, who were admitted within the last 1 year due to esophageal cancer in three affiliated hospitals of Zhengzhou University and Anyang Tumor Hospital, were enrolled. In addition, telephone surveys were conducted to investigate their awareness about endoscopic screening. One child was corresponded to an esophageal cancer patient. About half (47.6%, 111/233) of the children were unaware that endoscopic screening could detect early esophageal cancer and precancerous lesion. There was no significant difference in their awareness rates between hospitals with different administration levels. Besides, the males who had a lower family income and lower education level showed a poor awareness rate (P < 0.05). The overall awareness rate among the accompanying children of patients on endoscopic screening was rather low in Henan province (China). Hence, the health education and awareness on the importance of endoscopic screening for early detection of esophageal cancer should be promoted among children accompanying the patients. More attention should be focused towards the subject group, particularly among those male children with lower educational level and family income.

Comparison of prognostic factors of esophageal cancer between a Chinese cohort and the Surveillance, Epidemiology, and End Results (SEER) database: a retrospective cohort study

Background

Esophageal cancer is a highly aggressive, early metastasis gastrointestinal malignancy, with geographic differences in prognosis. It is unknown whether there are differences in the survival in different regions among esophageal cancer patients who underwent the treatments. This study was to explore the influencing factors of esophageal cancer survival in patients from China and the Surveillance, Epidemiology, and End Results (SEER) database.

Methods

The retrospective cohort study were conducted with 605 Chinese esophageal cancer patients in the Wuxi People's Hospital and 2,351 patients from the SEER database. The demographic and clinical data were collected from the two cohort, respectively. The outcome was the death during the follow-up. The follow-up ended on November 30, 2021. The Cox proportional hazards model was used in the univariate and multivariate survival analyses, with hazard ratio (HR) and 95% confidence interval (CI).

Results

In group one, the following were identified as the prognostic factors: female gender (HR =0.568; 95% CI: 0.398-0.811), T3 and T4 stages (HR =3.312; 95% CI: 2.493-4.401), N2 and N3 stages (HR =3.562; 95% CI: 2.631-4.824), and other subtypes of cancer (HR =0.393; 95% CI: 0.223-0.693). The following prognostic were factors identified in group two: age ≥65 years (HR =1.16; 95% CI: 1.058-1.276), female gender (HR =0.843; 95% CI: 0.752-0.945), T3 and T4 stages (HR =1.523; 95% CI: 1.373-1.690), M1 stage (HR =2.554; 95% CI: 2.303-2.832), treatment with surgery and chemotherapy (HR =0.507; 95% CI: 0.457-0.562), and other subtypes of cancer (HR =1.432; 95% CI: 1.298-1.581).

Conclusions

There may be some differences in prognostic factors between Chinese and American patients with esophageal cancer. It is indicated that different management strategies of esophageal cancer should be considered in different populations to improve the prognosis of patients.

Epiplakin1 promotes the progression of esophageal squamous cell carcinoma by activating the PI3K-AKT signaling pathway

BACKGROUND

Epiplakin1 (EPPK1) has been associated with disease progression and unfavorable prognosis of many cancers, but its functional involvement in esophageal squamous cell carcinoma (ESCC) remains to be uncovered.

METHODS

The Quantitative Real-time PCR (qPCR) assay was employed to determine the expression of EPPK1 in ESCC tissues and cells. CCK-8 assay, colony forming assay, wound healing assay, and transwell invasion assay were utilized to evaluate the effects of EPPK1 on cell proliferation, migration, and invasion capacity in ESCC cells using small interfering ribonucleic acids. Flow cytometry was performed to estimate the cell apoptotic rate caused by silencing of EPPK1. The proteins related to epithelial-to-mesenchymal transition (EMT), apoptosis, and activation of the phosphatidylinositol 3-kinase/serine threonine protein kinase 1 (PI3K/AKT) signaling pathway were measured by western blot.

RESULTS

The expression of EPPK1 was dramatically increased in ESCC tissues and cells compared to that in relative controls. Additionally, silencing of EPPK1 suppressed ESCC cell growth, colony formation, migration, invasion, and EMT, while promoting ESCC cell apoptosis. Furthermore, EPPK1 induced ESCC cell progression via mediating the PI3K/AKT signaling pathway.

CONCLUSION

EPPK1 promotes ESCC progression by modulating the PI3K/AKT signaling pathway and could serve as a potential target for ESCC treatment.

LncRNA DDX11 antisense RNA 1 promotes EMT process of esophageal squamous cell carcinoma by sponging miR-30d-5p to regulate SNAI1/ZEB2 expression and Wnt/β-catenin pathway

LncRNA DDX11 antisense RNA 1 (DDX11-AS1) is recognized as having an imperative oncogenic role in different types of human cancer. Nevertheless, the functions, as well as the basic mechanisms of DDX11-AS1 in the EMT process of esophageal squamous cell carcinoma (ESCC), are yet to be clarified. In this research, high DDX11-AS1 expression was detected in ESCC cells as well as tissues and was linked to the poor prognosis of patients with ESCC. DDX11-AS1 promoted cell proliferation, migration, invasion ability and epithelial mesenchymal transition (EMT) process in vitro. Mechanistic analysis depicted that DDX11-AS1 may function as a ceRNA through sponging miR-30d-5p to upregulate the expression of SNAI1 and ZEB2. Meanwhile, overexpression of DDX11-AS1 might cause the activation of the Wnt/β-catenin signaling pathway via targeting miR-30d-5p. On the whole, the findings of this research illustrate that DDX11-AS1 may act as an EMT-related lncRNA to advance ESCC progression through sponging miR-30d-5p to regulate SNAI1/ZEB2 expression and activate the Wnt/β-catenin pathway, which indicates that it might serve as a probable therapeutic target for ESCC.

SNHG17, as an EMT-related lncRNA, promotes the expression of c-Myc by binding to c-Jun in esophageal squamous cell carcinoma

Dysregulation of long noncoding RNA SNHG17 is associated with the occurrence of several tumors; however, its role in esophageal squamous cell carcinoma (ESCC) remains obscure. The present study demonstrated that SNHG17 was upregulated in ESCC tissues and cell lines, induced by TGF‐β1, and associated with poor survival. It is also involved in the epithelial‐to‐mesenchymal transition (EMT) process. The mechanism underlying SNHG17‐regulated c‐Myc was detected by RNA immunoprecipitation, RNA pull‐down, chromatin immunoprecipitation, and luciferase reporter assays. SNHG17 was found to directly regulate c‐Myc transcription by binding to c‐Jun protein and recruiting the complex to specific sequences of the c‐Myc promoter region, thereby increasing its expression. Moreover, SNHG17 hyperactivation induced by TGF‐β1 results in PI3K/AKT pathway activation, promoting cells EMT, forming a positive feedback loop. Furthermore, SNHG17 facilitated ESCC tumor growth in vivo. Overall, this study demonstrated that the SNHG17/c‐Jun/c‐Myc axis aggravates ESCC progression and EMT induction by TGF‐β1 and may serve as a new therapeutic target for ESCC.

FOXD3 suppresses epithelial-mesenchymal transition through direct transcriptional promotion of SMAD7 in esophageal squamous cell carcinoma

The transcription factor forkhead box D3 (FOXD3) is an important member of the FOX family, which can maintain the pluripotent properties of cell clusters, neural crest, and trophoblastic progenitor cells in vivo. It has been shown that FOXD3 could affect proliferation, migration, and angiogenesis of various tumors and its deletion and overexpression in organisms will undoubtedly have important influence on the change of cell fate and the occurrence of tumors. However, the underlying functions and molecular mechanisms of FOXD3 in esophageal squamous cell carcinoma (ESCC) have not been fully clarified. According to the present study, the expression levels and functional roles of FOXD3 were investigated, and its prognostic value and molecular mechanisms in tumorigenesis and progression of ESCC were clarified. The expression level of FOXD3 was significantly downregulated in ESCC tissues and cell lines, and correlated with gender, family history of upper gastrointestinal cancer, TNM stage, depth of invasion, lymph node metastasis, and ESCC patients' survival. Moreover, FOXD3 inhibited cells migration and invasion as well as participated in TGF-β1 induced epithelial-mesenchymal transition process. Furthermore, a positive correlation between FOXD3 and SMAD family member 7 (SMAD7) was explored in ESCC. FOXD3 could directly bind to promoter regions of SMAD7 gene, leading to transcriptional promotion of SMAD7 in human esophageal cancer cells. Taken together, FOXD3 may play a tumor suppressor role in ESCC and may be applied as a new therapeutic target and prognostic marker for ESCC.

Downregulation of long non-coding RNA LOC101928477 correlates with tumor progression by regulating the epithelial-mesenchymal transition in esophageal squamous cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is one of the deadliest malignancies. There is a growing body of evidence showing that long non‐coding RNAs (lncRNAs) play critical roles in ESCC oncogenesis. The present study aimed to explore the role of LOC101928477, a newly discovered lncRNA, in the development and metastasis of ESCC.

Methods

In this study, real‐time PCR, western blotting, cell counting kit‐8 (CCK‐8), flow cytometry, colony formation, wound healing, transwell migration/invasion assay, immunofluorescence, and immunohistochemistry were used. We also applied an in situ xenograft mouse model and a lung metastasis mouse model to verify our findings.

Results

We determined that LOC101928477 expression was inhibited in ESCC tissue and ESCC cell lines when compared with controls. Moreover, forced expression of LOC101928477 effectively inhibited ESCC cell proliferation, colony formation, migration, and invasion via suppression of epithelial‐mesenchymal transition (EMT). Furthermore, LOC101928477 overexpression inhibited in situ tumor growth and lung metastasis in a mouse model.

Conclusions

Together, our results suggested that LOC101928477 could be a novel suppressor gene involved in ESCC progression.

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

Background

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

Methods

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

Results

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

Conclusion

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

miR-199a-3p suppresses progression of esophageal squamous cell carcinoma through inhibiting mTOR/p70S6K pathway

Dysregulation of microRNA contributes to multiple tumorigenic processes. Although downregulation of miR-199a-3p has been shown in many cancers, its effects on esophageal squamous cell carcinoma (ESCC) and the regulatory mechanism are still obscure. Here, we aim to evaluate the biological function and underlying mechanisms of miR-199a-3p in ESCC as well as its value to clinical treatment of ESCC. We first analyzed expression of miR-199a-3p in esophageal cancer by bioinformatic analysis and found that there were different opinions about expression of miR-199a-3p in esophageal cancer, and the following qRT-PCR assay demonstrated which was markedly downregulated in ESCC cells. Next, we increased the expression of miR-199a-3p in ESCC cells using miR-199a-3p mimics and demonstrated that overexpression of miR-199a-3p significantly inhibited cell proliferation, migration and invasion, as well as induced cell cycle retard and promoted apoptosis in ESCC. Furthermore, we explored the functional targets of miR-199a-3p and identified that overexpression of miR-199a-3p inhibited mTOR/p70S6K pathway, but stimulated PI3K/Akt pathway. Finally, we demonstrated that overexpression of miR-199a-3p enhanced proliferation-inhibiting effects of MK2206, an inhibitor of Akt, to ESCC cells, which might be related that MK2206 eliminated the activation of miR-199a-3p to p-Akt. These findings discover that miR-199a-3p might participate in the carcinogenesis process of ESCC, which provides a new insight for treatment of ESCC.

LncRNA FAM83H-AS1 promotes oesophageal squamous cell carcinoma progression via miR-10a-5p/Girdin axis

Long non-coding RNAs (lncRNAs) have been well demonstrated to emerge as crucial regulators in cancer progression, and they can function as regulatory network based on their interactions. Although the biological functions of FAM83H-AS1 have been confirmed in various tumour progressions, the underlying molecular mechanisms of FAM83H-AS1 in oesophageal squamous cell carcinoma (ESCC) remained poorly understood. To address this, we treated human oesophageal cancer cell line Eca109 cells with TGF-β and found FAM83H-AS1 was notably overexpressed. In the present study, FAM83H-AS1 was observed to be significantly up-regulated in ESCC tissues and was associated with TNM stage, pathological differentiation and lymph node metastasis. FAM83H-AS1 reinforced oesophageal cancer cell proliferation, migration and invasion, and participated in epithelial-to-mesenchymal transition (EMT) process at mRNA and protein levels. In addition, a concordant regulation between FAM83H-AS1 and its sense strand FAM83H was detected at the transcriptional and translational levels. Furthermore, FAM83H-AS1 could act as competing endogenous RNA to affect the expression of Girdin by sponging miR-10a-5p verified by RIP and luciferase reporter assays. Consequently, the study provided a unique perspective of FAM83H-AS1 in ESCC progression, which may be considered as potential biomarker and therapeutic target for ESCC therapy.

BRCA2 loss-of-function germline mutations are associated with esophageal squamous cell carcinoma risk in Chinese

Esophageal squamous cell carcinoma (ESCC) occurs with highest frequency in China with over 90% mortality, highlighting the need for early detection and improved treatment strategies. We aimed to identify ESCC cancer predisposition gene(s). Our study included 4,517 individuals. The discovery phase using whole-exome sequencing (WES) included 186 familial ESCC patients from high-risk China. Targeted gene sequencing validation of 598 genes included 3,289 Henan and 1,228 moderate-risk Hong Kong Chinese. A WES approach identified BRCA2 loss-of-function (LOF) mutations in 3.23% (6/186) familial ESCC patients compared to 0.21% (9/4300) in the ExAC East Asians (odds ratio [OR] = 15.89, p = 2.48 × 10^-10 ). BRCA2 LOF mutation frequency in the combined Henan cohort has significantly higher prevalence (OR = 10.55, p = 0.0035). Results were independently validated in an ESCC Hong Kong cohort (OR = 10.64, p = 0.022). One Hong Kong pedigree was identified to carry a BRCA2 LOF mutation. BRCA2 inactivation in ESCC was via germline LOF mutations and wild-type somatic allelic loss via loss of heterozygosity. Gene-based association analysis, including LOF mutations and rare deleterious missense variants defined with combined annotation dependent depletion score ≥30, confirmed the genetic predisposition role of BRCA2 (OR = 9.50, p = 3.44 × 10^-5 ), and provided new evidence for potential association of ESCC risk with DNA repair genes (POLQ and MSH2), inflammation (TTC39B) and angiogenesis (KDR). Our findings are the first to provide compelling evidence of the role of BRCA2 in ESCC genetic susceptibility in Chinese, suggesting defective homologous recombination is an underlying cause in ESCC pathogenesis, which is amenable to therapeutic options based on synthetic lethality approaches such as targeting BRCA2 with PARP1 inhibitors in ESCC.

Promoter hypermethylation-mediated downregulation of tumor suppressor gene SEMA3B and lncRNA SEMA3B-AS1 correlates with progression and prognosis of esophageal squamous cell carcinoma

Frequent deletions of tumor-suppressor genes at chromosome 3p21.3 have been detected in esophageal squamous cell carcinoma (ESCC). As a candidate tumor suppressor gene, semaphorin 3B (SEMA3B) is located at 3p21.3 and is frequently inactivated in several tumors. However, the role and inactivation mechanisms of SEMA3B and its antisense long non-coding RNA (lncRNA) SEMA3B-AS1 in the carcinogenesis of ESCC have not been fully elucidated. The present study was conducted to investigate the role, epigenetic inactivation mechanisms, and prognostic value of SEMA3B and SEMA3B-AS1 in ESCC tumorigenesis and prognosis. Frequent downregulation of SEMA3B and SEMA3B-AS1 was detected in esophageal cancer cells and ESCC tissues, and the expression level of SEMA3B and SEMA3B-AS1 in ESCC tissues was correlated with TNM stage and lymph node metastasis. SEMA3B and SEMA3B-AS1 shared the same CpG island in the promoter region and the expression of both genes might be regulated by the promoter methylation status. Furthermore, transcription factor Sp1 activated SEMA3B or SEMA3B-AS1 transcription and the promoter hypermethylation of SEMA3B and SEMA3B-AS1 influenced Sp1 binding ability. Moreover, over-expression of SEMA3B and SEMA3B-AS1 suppressed the viability and invasion of esophageal cancer cells in vitro. SEMA3B-AS1 influenced the protein expression of SEMA3B. SEMA3B or SEMA3B-AS1 expression and promoter methylation status were correlated with ESCC patients' survival. Thus, these findings suggest that SEMA3B and SEMA3B-AS1 may act as tumor suppressors and may serve as potential targets for antitumor therapy.

Aberrant promoter 2 methylation‑mediated downregulation of protein tyrosine phosphatase, non‑receptor type 6, is associated with progression of esophageal squamous cell carcinoma

The human protein tyrosine phosphatase, non‑receptor type 6 (PTPN6) gene is located on chromosome 12p13 and encodes an Mr 68,000 non‑receptor type protein‑tyrosine phosphatase. The PTPN6 gene has been considered as a candidate tumor suppressor in hematological and solid malignancies, and promoter methylation may be an epigenetic modification silencing its expression. However, the detailed role of PTPN6 and its promoter methylation status in the pathogenesis of esophageal squamous cell carcinoma (ESCC) has not been fully elucidated. The aim of the present study was to investigate PTPN6 expression in ESCC tissues and esophageal cancer cell lines, detect the effect of CpG hypermethylation on the activity of PTPN6, and additionally elucidate the role and prognostic significance of PTPN6 in ESCC tumorigenesis and progression. The expression of PTPN6 was identified to be significantly downregulated in esophageal cancer cell lines and ESCC tissues. Marked upregulation of PTPN6 was detected in 5‑aza‑2'‑deoxycytidine‑treated esophageal cancer cells, and frequent hypermethylation of the CpG sites within the P2 promoter (P2) was detected in ESCC tissues and esophageal cancer cell lines. The expression and methylation status of PTPN6 was associated with tumor node metastasis stage, pathological differentiation and lymph node metastasis in patients with ESCC. Aberrant hypermethylation of the P2 exhibited marked tumor specificity and was identified to be associated with the expression level of PTPN6. Downregulation and hypermethylation of PTPN6 were identified to be associated with poor ESCC patient survival. Furthermore, upregulation of PTPN6 inhibited the proliferation and invasion of esophageal cancer cells in vitro. The results of the present study suggest that PTPN6 may serve as a tumor suppressor in ESCC, and it may serve as a potential target for antitumor therapy.

Prevalence of hyperuricemia among the Chinese population of the southeast coastal region and association with single nucleotide polymorphisms in urate‑anion exchanger genes: SLC22A12, ABCG2 and SLC2A9

Genome‑wide association studies identified that a series of genes, including solute carrier family (SLC) 2 member 9 (SLC2A9), SLC 22 member 12 (SLC22A12) and ATP‑binding cassette sub‑family G member 2 (ABCG2) polymorphisms were associated with serum uric acid (SUA) levels in the present study. High incidence rates of hyperuricemia were reported in the Chinese population of the southeast coastal region; however, no evidence has confirmed the genetic association with SUA levels in this region. The present study aimed to investigate the association between uric acid levels and hyperuricemia, and genotypes of the Chinese population of the southeast coastal region. In the present study, a total of 1,056 healthy patients attending routine checkups were employed to investigate the incidence of hyperuricemia; 300 subjects were then randomly selected from the 1,056 patients for the identification of genetic polymorphisms of SLC2A9rs11722228, SLC22A12rs893006 and ABCG2rs2231142 via high‑resolution melting. The present study reported that the incidence rate of hyperuricemia was 32.6% (42.5% in males and 22.7% in females, respectively). The prevalence of ABCG2rs2231142 polymorphisms (CC, CA and AA) was 44.4, 44.8 and 11.8%, respectively; SLC2A9rs11722228 polymorphisms (CC, CT and TT) were reported to be 49.3, 40.3 and 10.3%, respectively. Additionally, SLC22A12rs893006 polymorphisms (CC, CT and TT) were determined to be 57.2, 38.7 and 4.1%, respectively. The SUA levels were observed to be statistically different among each investigated genotype of ABCG2rs2231142 (P=0.047). The A allele was significantly associated with an increased risk of hyperuricemia (odds ratio=2.405 and 1.133 for CA and AA, respectively). The present study reported that high incidence rates of hyperuricemia in the Chinese population of the southeast coastal region may be closely associated with the variants of ABCG2rs2231142. Whether polymorphisms of SLC2A9rs11722228 and SLC22A12rs893006 are involved in hyperuricemia require further investigation.

Aberrant methylation-mediated silencing of lncRNA CTC-276P9.1 is associated with malignant progression of esophageal squamous cell carcinoma

Downregulation and aberrant hypermethylation of long non-coding RNA CTC-276P9.1 have been detected in limited tumors. However, the distribution of methylated CpG sites and biological role of CTC-276P9.1 in esophageal squamous cell carcinoma (ESCC) progression and prognosis have not been fully clarified. The present study was to investigate the expression status and the distribution of methylated CpG sites within the three CpG islands of CTC-276P9.1, further to clarify its functional role and prognostic value in ESCC development and prognosis. Significant downregulation of CTC-276P9.1 was detected in esophageal cancer cells and ESCC tissues, and the expression of CTC-276P9.1 in ESCC tissues was associated with TNM stage, pathological differentiation, lymph node metastasis, and distant metastasis or recurrence. The expression level of CTC-276P9.1 in esophageal cancer cells was significantly reversed by treatment with 5-Aza-dC and TSA. The aberrant hypermethylation of the regions around the transcription start site was more tumor specific and associated with the expression levels of CTC-276P9.1. Moreover, histone modification may also participate in the regulation of CTC-276P9.1. Furthermore, over-expression of CTC-276P9.1 inhibited esophageal cancer cells proliferation and invasion in vitro, decreased the expression of proliferative markers and inhibited esophageal cancer cells invasion probably by regulating EMT. In addition, the dysregulation and hypermethylation of the regions around the transcription start site of CTC-276P9.1 were associated with poorer ESCC patients' survival. These findings suggest that CTC-276P9.1 may act as a tumor suppressor and may be employed as a new prognostic factor and therapeutic target for ESCC.

Clinical significance of the correlation between PLCE 1 and PRKCA in esophageal inflammation and esophageal carcinoma

Esophagitis and Barrett's esophagus are linked to esophageal squamous cell carcinoma and adenocarcinoma, respectively. However, the underlying mechanisms are still unclear. This study analyzed the expression levels of and correlation between PLCE1 and PRKCA in human esophagitis, carcinogen NMBA-induced rat esophagus, PLCE1 genetic deficient mouse esophageal epithelial tissues and human esophageal cancer cell line, integrated with Online oncology data sets. We found that the expression levels of both PLCE1 and PRKCA were significantly elevated in human esophagitis, esophageal squamous cell carcinoma, Barrett's esophagus, esophageal adenocarcinoma and in NMBA-treated rat esophageal epithelia. However, PRKCA and cytokines were significantly downregulated in PLCE1-deficient mouse esophageal epithelia, and knockdown of PLCE1 in human esophageal cancer cells led to reduction of PRKCA and cytokines. Finally, high expression of both PLCE1 and PRKCA is significantly associated with poor outcomes of the patients with esophageal cancers. In conclusion, this study defined the initiation and progression of esophageal inflammation and malignant transformation, in which the positive correlation of PLCE1 and PRKCA exhibits critical clinical significance.

Function of miR-25 in the invasion and metastasis of esophageal squamous carcinoma cells and bioinformatical analysis of the miR-106b-25 cluster

MicroRNAs (miRNAs/miRs) are a class of small, non-coding RNA molecules that serve a key function in carcinogenesis and tumor progression. Recent evidence indicates that miRNAs may act as powerful regulators of migration and invasion. The present study aimed to investigate the effect of miR-25 on the invasion and metastasis of KYSE-150 and EC109 esophageal squamous cell carcinoma (ESCC) cells, and predict the mechanism of this effect by bioinformatically analyzing the miR-106b-25 cluster. In order to alter the expression of miR-25 in the two cell lines, a miR-25 inhibitor or mimic were transfected into the cells, which were then studied via Transwell migration and invasion assays. Subsequently, the target genes of the miR-106b-25 cluster were predicted using miRanda, PicTar, TargetScan and miRTarbase, and the functions of the target genes were predicted via Gene Ontology term and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. Then, a protein-protein interaction (PPI) network was produced using the Search Tool for the Retrieval of Interacting Genes. The results revealed that overexpressing miR-25 led to significantly increased cell migration and invasion in KYSE150 and EC109 cells. Suppressing miR-25 resulted in significantly decreased cell migration and invasion in KYSE150 cells, while the result was not significant in EC109 cells. Target genes of the miR-106b-25 cluster were significantly enriched in the biological process regulation of cellular metabolic process and several cancer-associated pathways, such as those for glioma and melanoma. The PPI network revealed that PTEN, TP53, MDM2, E2F1, PRMT5, MCM2, RB1, CDKN1A, SHAD7 and EZH2 may serve core roles within the network and associate with one another during the pathogenesis of ESCC. These results indicate that a high expression of miR-25 promotes the invasion and metastasis of ESCC cells, while the influence of low expression of miR-25 differs with cells with different degrees of differentiation. Invasion and metastasis are not effected in cells with poor differentiation, while they were decreased in well differentiated cells. Furthermore, PTEN, TP53, MDM2, E2F1, PRMT5, MCM2, RB1, CDKN1A, SHAD7 and EZH2 may be targeted by the miR-106b-25 cluster, and act together to regulate the development of ESCC.

Aberrant Methylation-Mediated Silencing of lncRNA MEG3 Functions as a ceRNA in Esophageal Cancer

Maternally expressed gene 3 (MEG3), a long non-coding RNA (lncRNA), has tumor-suppressor properties and its expression is lost in several human tumors. However, its biological role in esophageal squamous cell carcinoma (ESCC) tumorigenesis is poorly defined. The present study determined the role and methylation status of MEG3 in esophageal cancer cells and ESCC clinical specimens, and further observed the competing endogenous RNA (ceRNA) activity of MEG3 in the pathogenesis and development of ESCC. Significant downregulation of MEG3 was detected in esophageal cancer cells and ESCC tissues and the expression level of MEG3 was significantly increased in cancer cells after treated with the DNA methyltransferase inhibitor 5-Aza-dC. Upregulation of MEG3 led to the inhibition of proliferation and invasiveness of the cancer cells. The aberrant promoter hypermethylation of MEG3 indicates silencing of its expression. Furthermore, MEG3 acts as a ceRNA to regulate the expression of E-cadherin and FOXO1 by binding hsa-miR-9. Upregulation of miR-9 was detected in esophageal cancer cell lines and ESCC tissues, and miR-9 promoted esophageal cancer cell proliferation and invasion. Finally, downregulation and hypermethylation of MEG3 was associated with ESCC patients' survival.Implications: MEG3 functions as a tumor-suppressive lncRNA and aberrant promoter hypermethylation is critical for MEG3 gene silencing in ESCC. In addition, MEG3 acts as a ceRNA to regulate expression of E-cadherin and FOXO1 by competitively binding miR-9 and may be used as a potential biomarker in predicting ESCC patients' progression and prognosis. Mol Cancer Res; 15(7); 800-10. ©2017 AACR.

Aberrant methylation of DACT1 and DACT2 are associated with tumor progression and poor prognosis in esophageal squamous cell carcinoma

BACKGROUND

The DACT (Dishevelled-associated antagonist of β-catenin) family of scaffold proteins may play important roles in tumorigenesis. However, the epigenetic changes of DACT1, 2, 3 and their effect on esophageal squamous cell carcinoma (ESCC) have not been investigated so far. The aim of this study was to investigate the promoter methylation and expression of DACT family, in order to elucidate more information on the role of DACT with regard to the progression and prognosis of ESCC.

METHODS

MSP and BGS methods were respectively applied to examine the methylation status of DACT; RT-PCR, Western blot and immunohistochemistry methods were respectively used to determine the mRNA and protein expression of DACT; MTT, Colony-formation and Wound-healing assay were performed to assess the effect of DACT1 and DACT2 on proliferation and migration of esophageal cancer cells.

RESULTS

Frequent reduced expression of DACT1, DACT2 and DACT3 were found in esophageal cancer cell lines and the expression levels of DACT1 and DACT2 were reversed by 5-Aza-Dc. Decreased mRNA and protein expression of DACT1 and DACT2 were observed in ESCC tumor tissues and were associated with the methylation status of transcription start site (TSS) region. The hypermethylation of CpG islands (CGI) shore region in DACT1 was observed both in tumor and corresponding adjacent tissues but wasn't related to the transcriptional inhibition of DACT1. The methylation status of TSS region in DACT1 and DACT2 and the protein expression of DACT2 were independently associated with ESCC patients' prognosis.

CONCLUSIONS

The TSS region hypermethylation may be one of the main mechanisms for reduced expression of DACT1 and DACT2 in ESCC. The simultaneous methylation of DACT1 and DACT2 may play important roles in progression of ESCC and may serve as prognostic methylation biomarkers for ESCC patients.

Updated incidence rates and risk factors of esophageal cancer in Nan'ao Island, a coastal high-risk area in southern China

Esophageal cancer (EC) is one of the most common cancers in China. The purpose of this study was to investigate the updated incidence rates and risk factors of EC in Nan'ao Island, where the EC incidence rate was chronically the highest in southern China. To calculate the annual incidence rate, data on 338 EC cases from Nan'ao Cancer Registry system diagnosed during 2005-2011 were collected. A case-control study was conducted to explore the EC risk factors. One hundred twenty-five alive EC patients diagnosed during 2005-2011 and 250 controls were enrolled into the case-control study. A pre-test questionnaire on demography, dietary factors, drinking water treatment, and behavioral factors was applied to collect information of all participants. The average EC incidence rates during 2005-2011 were 66.09/105, 94.62/105, 36.83/105 for both genders, males and females, respectively, in Nan'ao Island. The EC incidence rate in males was 2.40- to 4.55-fold higher than that in females in the period from 2006 to 2011 (P < 0.05). Considering the onset age, males tend to be much younger than females and reached peak incidence rate at a younger age (P < 0.05). Drinking water treatment by filter (odds ratio [OR] = 0.28, 95% confidence interval [95% CI] = 0.13-0.58) and fruit consumption (OR = 0.55, 95% CI = 0.32-0.94) reduced the risk for EC. On the contrary, the pickled vegetables consumption (OR = 2.64, 95% CI = 1.46-4.76) and liquor drinking (OR = 2.32, 95% CI = 1.21-4.44) increased the risk for EC. These results may be of importance for future research on EC etiology and prevention strategies.

Expression and clinical significance of C14orf166 in esophageal squamous cell carcinoma

C14orf166, a 28 kD protein regulating RNA transcription and translation, may serve a critical role in oncogenesis. The aim of the current study was to explore the association between C14orf166 expression and esophageal squamous cell carcinoma (ESCC) and to draw attention to the association between C14orf166 and the initiation, progression and prognosis of ESCC. C14orf166 expression in ESCC and paired normal tissues was detected by immunohistochemical staining, western blotting and reverse transcription-quantitative polymerase chain reaction, and the association between C14orf166 expression and clinicopathological characters of ESCC was analyzed. Survival analysis was used to assess the prognostic significance of C14orf166 and it was observed that C14orf166 expression was higher in the ESCC tissues when compared with adjacent non-cancerous tissues at protein (P<0.001) and mRNA levels (P<0.001). There was a significant difference in T stage, lymph node metastasis and TNM stage in patients categorized according to different C14orf166 expression levels. The overexpression of C14orf166 was associated with a shorter overall survival and disease-free survival, and multivariate analysis indicated that C14orf166 was an independent prognostic indicator. The present study indicates that the expression of C14orf166 is elevated in ESCC, and is potentially a valuable prognostic predictor for ESCC.

A genetic polymorphism at miR-526b binding-site in the lincRNA-NR_024015 exon confers risk of esophageal squamous cell carcinoma in a population of North China

Esophageal squamous cell carcinoma (ESCC) may be caused by a combination of environmental factors and genetic variants. The present study was to evaluate the association between haplotype-tagging SNPs (htSNPs) of lincRNA-NR_024015 and the risk of ESCC. We selected htSNPs across the whole 1469 bp lincRNA-NR_024015 locus and 2 kb upstream as well as 2 kb downstream regions of the gene and conducted a case-control study in 581 ESCC cases and 677 healthy controls to test the effects of functional lincRNA-NR_024015 htSNPs on ESCC susceptibility. Of the seven potential functional htSNPs, rs8506 AA genotype was found to be associated with increased risk of ESCC. Further stratification analysis showed that the risk effect was more pronounced in male patients and patients with TNM stage III and IV. LincRNA-NR_024015 was predominantly expressed in cytoplasm of esophageal cancer cells. The expression level of lincRNA-NR_024015 in ESCC tumor tissues was significantly higher than that in corresponding normal tissues and rs8506 genotype has a genotype-specific effect on lincRNA-NR_024015 expression. Furthermore, rs8506 G to A variant might influence lincRNA-NR_024015 expression and function by disrupting the binding of hsa-miR-526b to the site. High expression level of lincRNA-NR_024015 and rs8506 A allele were associated with poor ESCC patients' survival. These findings indicate that functional polymorphism rs8506 G>A in lincRNA-NR_024015 exon may be a genetic modifier for the development of ESCC and lincRNA-NR_024015 may be a useful marker for the prediction of the biological behavior of ESCC. © 2016 Wiley Periodicals, Inc.

Aberrant methylation-mediated downregulation of long noncoding RNA LOC100130476 correlates with malignant progression of esophageal squamous cell carcinoma

BACKGROUND

Dysregulated long non-coding RNAs (lncRNAs) are involved in many complicated human diseases including cancer.

AIMS

To determine the role and methylation status of a new lncRNA LOC100130476 in the pathogenesis of esophageal squamous cell carcinoma (ESCC).

METHODS

One hundred and twenty three ESCC patients with tumor tissues and corresponding adjacent normal tissues were enrolled. The expression level and methylation status of LOC100130476 in esophageal cancer cell lines and primary ESCC samples were respectively detected.

RESULTS

Significant downregulation of LOC100130476 was detected in esophageal cancer cell lines and primary ESCC tumor tissues. Up-regulation of LOC100130476 led to the inhibition of proliferation and invasiveness of the cancer cells. Aberrant hypermethylation of the CpG sites in exon 1 closing to the transcription start site was found to be more tumor-specific and to be more critical for gene silencing. Hypermethylation of these CpG sites was associated with TNM stage and pathological differentiation. ESCC patients in stage III and IV, with low expression or hypermethylation of the CpG sites in exon 1 demonstrated poor patient survival.

CONCLUSIONS

LOC100130476 is down-regulated in ESCC at least partly by hypermethylation of CpG sites in exon 1 and its hypermethylation may have prognostic implications for ESCC patients.

Aberrant hypermethylation of RASSF2 in tumors and peripheral blood DNA as a biomarker for malignant progression and poor prognosis of esophageal squamous cell carcinoma

As a tumor suppressor gene, RAS-association domain family 2 (RASSF2) is inactivated by promoter hypermethylation in different tumor cell lines and primary tumors. However, the role of RASSF2 in esophageal squamous cell carcinoma (ESCC) has remained uninvestigated. The aims of this study were to determine the role and methylation status of RASSF2 in esophageal cancer cell lines, ESCC tissues and white blood cells, and to evaluate the potential prognostic role of RASSF2 in ESCC. In the present study, we found frequent silencing of RASSF2 and up-regulation of the gene by 5-Aza-dC treatment in esophageal cancer cell lines. Aberrant methylation of the CpG sites close to the transcription start site induced silencing of RASSF2 expression and in vitro methylation of RASSF2 led to a significant decrease in luciferase activity. The results were further verified in clinical specimens and aberrant methylation of the CpG sites close to the transcription start site of RASSF2 was found in ESCC tumor tissues and peripheral white blood cells. Furthermore, RASSF2 hypermethylation was associated with lower level of RASSF2 expression. ESCC patients in stage III and IV, with negative expression or hypermethylation of the CpG sites close to the transcription start of RASSF2 demonstrated poor patient survival. Taken together, our results suggest that RASSF2 may function as a tumor suppressor gene that is inactivated through hypermethylation of CpG sites close to the transcription start site in ESCC and its expression or methylation may have prognostic implications for ESCC patients.

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

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

Long noncoding RNA SPRY4-IT1 promotes esophageal squamous cell carcinoma cell proliferation, invasion, and epithelial-mesenchymal transition

The biology of esophageal squamous cell carcinoma (ESCC) remains poorly understood. Long noncoding RNAs (lncRNAs) are found to be dysregulated in a variety of cancers, including ESCC. SPRY4-IT1 has been recently revealed as oncogenic regulator or tumor suppressors in different cancers; however, whether SPRY4-IT1 is involved in ESCC remains poorly understood. To investigate the role of SPRY4-IT1 in ESCC, we evaluated the SPRY4-IT1 expression levels in a series of ESCC patients and a panel of ESCC cell line using qRT-PCR. CCK8 and colony formation assay were performed to assess the effect of SPRY4-IT1siRNA on cell proliferation, migration, and invasion of ESCC cell lines. SPRY4-IT1 expression was upregulated in ESCC tissues and the higher expression of SPRY4-IT1 was significantly correlated with tumor grade, depth of invasion, and lymph node metastasis. Moreover, silencing of SPRY4-IT1 expression inhibited ESCC cell proliferation, colony formation, migration, and invasion. Therefore, our study indicates that SPRY4-IT1 promotes proliferation and migration of ESCC cells and is a potential oncogene of ESCC.

Comparison of clinicopathologic features and survival between eastern and western population with esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is the major histologic subtype of esophageal cancer, characterized by a high mortality rate and geographic differences in incidences. It is unknown whether there is difference between "eastern" ESCC and "western" ESCC. This study is attempted to demonstrate the hypothesis by comparing ESCC between Chinese residents and Caucasians living in the US.

METHODS

The data sources of this study are from United States SEER limited-use database and Shanghai Cancer Registries by Shanghai Municipal Center for Disease Control (SMCDC). Consecutive, non-selected patients with pathologically diagnosed ESCC, between January 1, 2002 and December 31, 2006, were included in this analysis. 1-year, 3-year and 5-year survival estimates were computed and compared between two populations. A Cox proportional hazards model was used to determine factors affecting survival differences.

RESULTS

A total of 1,718 Chinese, 1,624 Caucasians ESCC patients with individual American Joint Commission on Cancer (AJCC) staging information were included in this study. The Caucasian group had a significantly higher proportion of female patients than Chinese (38.24% vs. 18.68% P<0.01). ESCC was diagnosed in Chinese patients at an earlier age and stage than Caucasians. Generally, Chinese patients had similar overall survival rate with Caucasian by both univariate and multivariate analysis. Overall survival was significantly worse only in male Caucasians compared to Chinese patients (median survival time, 12.4 vs. 14.5 months, P<0.01, respectively).

CONCLUSIONS

ESCC from eastern and western countries might have some different features. These differences need to be taken into account for the management of ESCC patients in different ethnic groups.

Methylation-mediated repression of potential tumor suppressor miR-203a and miR-203b contributes to esophageal squamous cell carcinoma development

MiRNAs regulate gene expression and play pivotal roles in biological processes. MiRNAs can be inactivated by epigenetic mechanisms, such as DNA hypermethylation of CpG sites within CpG islands. Here, we investigated the role and methylation status of miR-203a and miR-203b in esophageal cancer cell lines and primary esophageal squamous cell carcinoma (ESCC) tumors and further elucidate the role of both miRNAs in the prognosis of ESCC. The present study revealed a strong downregulation of miR-203a and miR-203b in esophageal cancer cell lines and primary ESCC samples. Treatment of esophageal cancer cells with demethylating agent 5-Aza-dC led to increased miR-203a and miR-203b expression, confirming the epigenetic regulation of both miRNAs. The inhibition of proliferation and invasiveness in esophageal cancer cells after treated with 5-Aza-dC or transfected with miR-203a or miR-203b mimics, suggesting the tumor suppressor role of both miRNAs in esophageal cancer. Furthermore, the critical CpG sites of miR-203a and miR-203b were found to be located in proximal promoter region, and the proximal promoter hypermethylation of both miRNAs was found to influence transcriptional activity. Downregulation and hypermethylation of miR-203a and miR-203b were associated with TNM stage, pathological differentiation, and lymph node metastasis. ESCC patients in stages III and IV, with reduced expression of miR-203a or hypermethylation of miR-203a or miR-203b, demonstrated poor patient survival. In summary, our results suggest that miR-203a and miR-203b may function as tumor-suppressive miRNAs that are inactivated through proximal promoter hypermethylation and miR-203a expression and methylation may be useful prognostic marker in ESCC patients.

A versatile orthotopic nude mouse model for study of esophageal squamous cell carcinoma

Increasing evidence indicates tumor-stromal interactions play a crucial role in cancer. An in vivo esophageal squamous cell carcinoma (ESCC) orthotopic animal model was developed with bioluminescence imaging established with a real-time monitoring platform for functional and signaling investigation of tumor-stromal interactions. The model was produced by injection of luciferase-labelled ESCC cells into the intraesophageal wall of nude mice. Histological examination indicates this orthotopic model is highly reproducible with 100% tumorigenesis among the four ESCC cell lines tested. This new model recapitulates many clinical and pathological properties of human ESCC, including esophageal luminal stricture by squamous cell carcinoma with nodular tumor growth, adventitia invasion, lymphovascular invasion, and perineural infiltration. It was tested using an AKT shRNA knockdown of ESCC cell lines and the in vivo tumor suppressive effects of AKT knockdown were observed. In conclusion, this ESCC orthotopic mouse model allows investigation of gene functions of cancer cells in a more natural tumor microenvironment and has advantages over previous established models. It provides a versatile platform with potential application for metastasis and therapeutic regimen testing.

RASSF5A, a candidate tumor suppressor, is epigenetically inactivated in esophageal squamous cell carcinoma

As a result of alternative splicing and differential promoter usage, RASSF5 exists in at least three isoforms (RASSF5A-RASSF5C), which may play different roles in tumorigenesis. The present study was to detect the role of RASSF5A, B and C in esophageal squamous cell carcinoma (ESCC) and clarify the critical CpG sites of RASSF5A, in order to clarify more information on the role of RASSF5 with regard to the pathogenesis of ESCC. Frequent silencing of RASSF5A but not RASSF5B and RASSF5C were found in esophageal cancer cell lines and the silencing of RASSF5A may be reversed by 5-Aza-dC or TSA treatment. The aberrant CpG island 1 methylation of RASSF5A induces silencing of its expression in TE13 cell line. Decreased mRNA and protein expression of RASSF5A was observed in ESCC tumor tissues and was associated with RASSF5A CpG island 1 methylation status. Unlike RASSF5A, expression variation of RASSF5B and RASSF5C was not found in ESCC tissues. Aberrant promoter methylation of RASSF5C was also not found in ESCC. RASSF5A methylation and protein expression were independently associated with ESCC patients' survival. These data indicated that the inactivation of RASSF5A through CpG island 1 methylation may play an important role in ESCC carcinogenesis, RASSF5A may be a functional tumor suppressor and may serve as a prognostic biomarker for ESCC.

Development of esophageal cancer in Chaoshan region, China: association with environmental, genetic and cultural factors

Esophageal squamous cell carcinoma (ESCC) is the eighth most common cancer by incidence worldwide. Although the cancer is located at a readily recognizable and accessible site in the body, it is the sixth most common cause of cancer death. The 1- and 5-year survival rates in China are 50% and 15%, respectively. Furthermore, the cancer has distinct geographic and etiological risk factors in different locations around the world. Since ESCC is highly prevalent in the Chaoshan (Southeastern) region of China, this report will focus on a review of risk factors for the cancer in this area. From the review, it is clear that some important and traditional factors are involved, e.g. environmental mutagens, genetic predisposition. However, unique factors, e.g. the drinking of very hot tea, may play an important role. This review highlights the role of complex risk factors (environmental, genetic and cultural) which contribute to the multistage development of cancer: localized injury, inflammation, mitogenesis, mutagenesis, carcinogenesis and eventually mortality. The latter is contributed by unnecessary delay in seeking medical care which may be culturally related. The review emphasizes the need to identify causal mechanisms for the complex carcinogenic process which can provide opportunity for prevention and treatment of this potentially curable cancer.

Tumor suppression by miR-31 in esophageal carcinoma is p21-dependent

microRNA regulation network is important for the cancer genetic heterogeneity. Relative to the increasing numbers of microRNA's targets identified, upstream regulatory mechanisms that control functional microRNAs are less well-documented. Here, we investigated the function of miR-31, a pleiotropically-acting microRNA, in esophageal squamous cell cancer (ESCC). We demonstrated that miR-31 only exerted tumor-suppressive effects in TE-7 ESCC cells, but not in TE-1 ESCC cells, although both of these cell lines harbor inactive p53. Interestingly, TE-1 cells highly expressed p21, while p21 levels were virtually undetectable in TE-7 cells, suggesting a p21-dependent mechanism of miR-31-mediated tumor suppression. Accordingly, knockdown of p21 in TE-1 cells reversed the tumor suppressive actions of miR-31. In patient ESCC specimens, real-time RT-PCR analysis revealed that expression of E2F2 and STK40, two known miR-31 target oncogenes, was negatively correlated with the expression of miR-31 in a p21-dependent manner, supporting the conclusion that miR-31 only downregulates its target oncogenes when p21 levels are low. Collectively, these data suggest a novel mechanism through which the tumor-suppressive effect of miR-31 is p21-dependent. In addition, we speculate that delivery of miR-31 could provide therapeutic benefit in the personalized management of a subgroup of ESCC patients with p21-deficient tumors.

MicroRNAs related polymorphisms and genetic susceptibility to esophageal squamous cell carcinoma

Esophageal cancer (EC) is the sixth leading cause of cancer-associated death worldwide and the incidence and mortality in China are the highest. The single nucleotide polymorphisms (SNPs) related to microRNAs could lead to alteration in microRNA expression and contribute to the susceptibility of cancer. To evaluate the association between microRNA-related SNPs and EC, a case-control study including 381 patients with esophageal squamous cell carcinoma (ESCC) and 426 gender, age-matched controls was carried out to investigate the genetic susceptibility of five microRNA-related SNPs (rs2910164 in microRNA-146a, rs11614913 in microRNA-196a-2, rs7813 in GEMIN4, rs1595066 and rs16845990 in ErbB4) as well as the interactions of gene-gene and gene-environment in the development of ESCC. Variant homozygote genotype of rs11614913 in microRNA-196a-2 and rs1595066 in ErbB4 were significantly associated with reduced ESCC risk (OR(adjusted): 0.62, 95 % CI: 0.39-0.99 and OR(adjusted): 0.38, 95 % CI: 0.24-0.61). The analysis of haplotypes in ErbB4 gene showed significant increased ESCC risk in G(rs1595066)C(rs16845990) and G(rs1595066)T(rs16845990) haplotypes (OR(adjusted): 1.46, 95 % CI: 1.08-1.99 and OR(adjusted): 1.33, 95 % CI: 1.10-1.62), and inversely reduced ESCC risk in A(rs1595066)C(rs16845990) and A(rs1595066)T(rs16845990) haplotypes with OR (95 % CI) of 0.75 (0.60-0.94) and 0.65 (0.49-0.86), respectively. These findings suggest that the polymorphisms in the microRNA-related genes may affect susceptibility of ESCC in Chinese Han population and the gene-gene interactions play vital roles in the progression on esophageal cancer. Future studies with larger sample and different ethnic populations are required to support and validate our findings.

Identity-by-descent approaches identify regions of importance for genetic susceptibility to hereditary esophageal squamous cell carcinoma

Worldwide, the highest prevalence of esophageal cancer (EC) occurs in Northern China. High-density SNP arrays allow identification of identity-by-descent (IBD) segments in genomic DNAs representative of shared common ancestral regions. We utilized IBD approaches to map susceptibility loci associated with low-penetrance SNPs in high-risk Henan hereditary esophageal squamous cell carcinoma (ESCC) patients. Affymetrix GeneChip Human mapping SNP array IBD analysis was performed in 32 Henan family history-positive (FH+) ESCC patients, 18 Henan healthy unrelated individuals, and 45 Chinese individuals from a CHB HapMap dataset using PLink (scoring IBD segments individually) and Beagle (scoring of shared IBD segments among case/case vs. control/control pairs) software. Both analyses identified longer IBD segment lengths associated with FH+ ESCC compared to controls. However, there was no strong evidence for a genetic founder effect. Pairing IBD analysis with BEAGLE identified 8 critical IBD segments residing at 2q32.1-q32.2, 3p22.3-p22.2, 4q21.1-q21.21, 7p22.2, 8q23.2-q23.3, 10q23.33-q24.1, 14q24.3 and 16q11.2-q12.1, which were more significantly shared among case/case compared to control/control. The shared IBD segments in FH+ ESCC samples with no overlap with control/CHB Hapmap may encompass potential cancer susceptibility loci. Selected targeted genes, PLCE1, GPT2, SIAH1 and CYP2C-18, residing within the IBD segments at 10q23.33-q24.1 and 16q11.2-q12.1, had statistically significant differential expression in primary ESCC tissues and are likely involved in ESCC carcinogenesis. The importance of these IBD segments to the etiology and development of ESCC in high-risk areas requires further study with expanded sample sizes. This is the first report employing the pairing IBD approach for elucidation of the genetic basis of hereditary ESCC in Henan by applying high throughput SNP array analysis.

Genetic epidemiological analysis of esophageal cancer in high-incidence areas of China

Genetic epidemiological studies have shown that genetic susceptibility to esophageal cancer (EC) is an important cause of its high incidence within families in some areas of China. The purpose of this study was to obtain evidence of a genetic basis of EC in Xin-an and Xin-xiang counties in China. Familial aggregation and complex segregation analyses were performed of 79 EC families in these counties. The heritability of EC was examined using Falconer's method and complex segregation analysis was conducted with the SEGREG program in Statistical Analysis for Genetic Epidemiology (SAGE version 5.3.1). The results showed that the distribution of EC in families did not fit well into a binomial distribution. The heritability of EC among first-degree and second- degree relatives was 67.0±7.31% and 43.1%±9.80%, respectively, and the summing up powered heritability was 53.2±6.74%. The segregation ratio was 0.045. Complex segregation analysis showed that the genetic model of EC was additive. The current results provide evidence for an inherited propensity to EC in certain high-risk groups in China, and support efforts to identify the genes that confer susceptibility to this disease.

Hsa-miR-196a2 functional SNP is associated with the risk of ESCC in individuals under 60 years old

BACKGROUND AND AIM

The miR-196a2 gene contains a C/T polymorphism (rs11614913). Its presence could change the conformation of secondary structure of miR-196a2 RNA, and directly affect the binding to target mRNAs and the miRNA maturation process. Both of which eventually alter protein expression and contributed to cancer susceptibility. This study assessed whether the rs11614913 single nucleotide polymorphism (SNP) could affect an individual's susceptibility to esophageal squamous cell carcinomas (ESCC).

METHODS

SNP rs11614913 was genotyped by polymerase chain reaction ligase detection reaction (PCR-LDR) in 597 ESCC patients and 597 control subjects.

RESULTS

Overall, there were no significant differences in the frequency of the miRNA-196a2 SNP rs11614913 genotype between the ESCC cases and the controls (χ(2) = 1.395, p = 0.498). The TT genotype, CT genotype and CT/TT combined genotype (dominant model) did not modify the risk of ESCC as compared with the CC genotype. Comparisons of the TT genotype to the CT/CC combined genotype did not reveal a significant association to ESCC, too. However, further analyses revealed an increased risk of ESCC in the dominant model (OR = 1.56, 95% CI = 1.08-2.26) and the allele frequency comparison (OR = 1.31, 95% CI = 1.06-1.63) in the ≤60-year-old group.

CONCLUSIONS

These results suggest that the miRNA-196a2 functional polymorphism rs11614913 might be an effective genetic marker for ESCC risk assessment in individuals younger than 60 years of age from a region of high ESCC incidence in northern China.

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.

Polymorphism of A133S and promoter hypermethylation in Ras association domain family 1A gene (RASSF1A) is associated with risk of esophageal and gastric cardia cancers in Chinese population from high incidence area in northern China

Background

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).

Methods

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.

Results

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).

Conclusions

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.

Novel functional variants locus in PLCE1 and susceptibility to esophageal squamous cell carcinoma: based on published genome-wide association studies in a central Chinese population

A novel functional single nucleotide polymorphism (SNP) rs2274223 located in the 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. In the present study, we validated this finding and also explored the risk of ESCC associated with other two unreported potentially functional SNPs (rs17417407 G>T and rs2274224 C>G) of PLCE1 in a population-based case-control study to investigate the association between these three potentially functional SNPs in PLCE1 and susceptibility to ESCC. A total of 381 ESCC cases and 420 controls matched by age and sex were recruited and successfully genotyped for three SNPs (rs17417407, rs2274223 and rs2274224) of the PLCE1 in a central Chinese population. SNP rs2274223 was independently associated with increased risk of ESCC (adjusted odds ratio [OR], 2.80; 95% confidence interval [95% CI], 1.45-5.39 for GG vs. AA), and SNP rs2274224 was found to be associated with decreased risk of ESCC (adjusted OR, 0.65; 95% CI, 0.46-0.91 for CG vs. CC). The combined effects of risk alleles for three SNPs (rs17417407T, rs2274223G and rs2274224G) were found to be associated with elevated risk of ESCC in a dose-dependent effect manner (Ptrend=0.005). The Grs17417407Ars2274223Crs2274224 haplotype decreased the risk of ESCC (adjusted OR, 0.76; 95% CI, 0.62-0.93), meanwhile the Grs17417407Grs2274223Crs2274224 and Trs17417407Grs2274223Crs2274224 haplotypes could increase the risk of ESCC (adjusted OR, 1.75; 95% CI, 1.33-2.18 and OR, 2.51; 95% CI, 1.15-2.49). Gene-environment interaction analysis presented a best model consisted of four factors (rs2274223, rs2274224, family history, and smoking) with testing balance accuracy (TBA): 0.66 and cross validation consistency (CVC): 7/10, which could increase the esophageal cancer risk in the "high risk group" with 3.67-fold (OR: 3.67, 95% CI: 2.74-4.92), compared to the "low risk group". Our results further confirmed that genetic variations in PLCE1 may contribute to ESCC risk associated with tobacco exposure in a central Chinese population. Further functional studies are needed to validate our results.

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

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

Esophageal squamous cell carcinoma and gastric cardia adenocarcinoma shared susceptibility locus in PLCE1: a meta-analysis

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

Our meta-analysis results indicated that PLCE1 rs2274223 G allele significantly contributed to the risk of ESCC and GCA, especially in Chinese population.

PLC-ε1 gene polymorphisms significantly enhance the risk of esophageal squamous cell carcinoma in individuals with a family history of upper gastrointestinal cancers

BACKGROUND AND AIMS

Phospholipase C epsilon 1 (PLCε1) may regulate cell growth, differentiation, apoptosis and angiogenesis and play an important role in carcinogenesis and the progression of several cancers. This study was designed to validate the association of the PLCε1 rs2274223 single nucleotide polymorphism (SNP) with esophageal squamous cell carcinoma (ESCC) as identified by genome-wide association studies (GWAS) and further assess whether the rs11599672 SNP could affect an individual's susceptibility to ESCC.

METHODS

These two SNPs were genotyped by polymerase chain reaction ligase detection reaction (PCR-LDR) in 527 ESCC patients and 527 controls.

RESULTS

Compared with the rs2274223 SNP AA genotype, other genotypes or combined genotypes all enhanced the risk of ESCC. Further analyses showed that AG/GG genotype carriers with a family history of upper gastrointestinal cancers (UGIC) had an increased risk of ESCC than those AA genotype carriers without UGIC family history (OR = 2.10, 95% CI = 1.46-3.10). Overall, rs11599672 SNP had no influence on ESCC susceptibility. However, UGIC family history elevated the risk of ESCC for subjects with the TT genotype (OR = 1.59, 95% CI = 1.13-2.24).

CONCLUSIONS

These results highlighted the role of a genetic factor in ESCC and suggested that the PLCε1 rs2274223 SNP might be an effective genetic marker to assess the risk of ESCC in individuals with a UGIC family history from a region of high incidence in northern China.

Aberrant methylation of different DNA repair genes demonstrates distinct prognostic value for esophageal cancer

BACKGROUND

DNA mismatch repair (MMR) deficiency results in a strong mutator phenotype and high-frequency microsatellite instability (MSI-H), which are the hallmarks of many tumors.

AIM

The objective of this study is to investigate the promoter CpG island methylation status of mismatch repair genes human mutL homolog 1 (hMLH1), human mutS homolog 2 (hMSH2), and O(6)-methylguanine-DNA methyltransferase (MGMT) in esophageal squamous cell carcinoma (ESCC) and its roles in alkylating agents chemotherapy.

METHODS

Real-time methylation-specific polymerase chain reaction (PCR) (real-time MSP) was employed to detect promoter CpG island methylation of the hMLH1, hMSH2, as well as MGMT genes in 235 surgical tumor tissue samples from ESCC patients and their corresponding normal tissue samples.

RESULTS

Promoter CpG island methylation of hMLH1, hMSH2, and MGMT were detectable in 43.4, 28.9, and 40.4% of ESCC tumor DNA, respectively, and the loss rates of hMLH1, hMSH2, and MGMT protein expression were 48.6, 34.5, and 40.9% in tumor tissues, respectively. For the entire population of 235 ESCC patients who were enrolled in operating treatment combined with radiotherapy and chemotherapy with alkylating agents, there was a significant difference in the overall survival between patients with methylated MGMT promoter and those with an unmethylated MGMT promoter (P < 0.05).

CONCLUSION

Promoter CpG island methylation may be a frequent event in ESCC carcinogenesis. Detection of the methylated sequences of hMLH1, hMSH2, and MGMT appears to be promising as a predictive factor in primary ESCC.

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

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