Genetic alterations in esophageal cancer and their relevance to etiology and pathogenesis: a review

A Genomic Analysis of Esophageal Squamous Cell Carcinoma in Eastern Africa

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) comprises 90% of all esophageal cancer cases globally and is the most common histology in low-resource settings. Eastern Africa has a disproportionately high incidence of ESCC.

METHODS

We describe the genomic profiles of 61 ESCC cases from Tanzania and compare them to profiles from an existing cohort of ESCC cases from Malawi. We also provide a comparison to ESCC tumors in The Cancer Genome Atlas (TCGA).

RESULTS

We observed substantial transcriptional overlap with other squamous histologies via comparison with TCGA PanCan dataset. DNA analysis revealed known mutational patterns, both genome-wide as well as in genes known to be commonly mutated in ESCC. TP53 mutations were the most common somatic mutation in tumors from both Tanzania and Malawi but were detected at lower frequencies than previously reported in ESCC cases from other settings. In a combined analysis, two unique transcriptional clusters were identified: a proliferative/epithelial cluster and an invasive/migrative/mesenchymal cluster. Mutational signature analysis of the Tanzanian cohort revealed common signatures associated with aging and cytidine deaminase activity (APOBEC) and an absence of signature 29, which was previously reported in the Malawi cohort.

CONCLUSIONS

This study defines the molecular characteristics of ESCC in Tanzania, and enriches the Eastern African dataset, with findings of overall similarities but also some heterogeneity across two unique sites.

IMPACT

Despite a high burden of ESCC in Eastern Africa, investigations into the genomics in this region are nascent. This represents the largest comprehensive genomic analysis ESCC from sub-Saharan Africa to date.

Aldehyde-Associated Mutagenesis─Current State of Knowledge

Aldehydes are widespread in the environment, with multiple sources such as food and beverages, industrial effluents, cigarette smoke, and additives. The toxic effects of exposure to several aldehydes have been observed in numerous studies. At the molecular level, aldehydes damage DNA, cross-link DNA and proteins, lead to lipid peroxidation, and are associated with increased disease risk including cancer. People genetically predisposed to aldehyde sensitivity exhibit severe health outcomes. In various diseases such as Fanconi's anemia and Cockayne syndrome, loss of aldehyde-metabolizing pathways in conjunction with defects in DNA repair leads to widespread DNA damage. Importantly, aldehyde-associated mutagenicity is being explored in a growing number of studies, which could offer key insights into how they potentially contribute to tumorigenesis. Here, we review the genotoxic effects of various aldehydes, focusing particularly on the DNA adducts underlying the mutagenicity of environmentally derived aldehydes. We summarize the chemical structures of the aldehydes and their predominant DNA adducts, discuss various methodologies, in vitro and in vivo, commonly used in measuring aldehyde-associated mutagenesis, and highlight some recent studies looking at aldehyde-associated mutation signatures and spectra. We conclude the Review with a discussion on the challenges and future perspectives of investigating aldehyde-associated mutagenesis.

MicroRNA-2053 involves in the progression of esophageal cancer by targeting KIF3C

This study aimed to explore the role of micorRNA-2053 in esophageal cancer development. The expression level of miR-2053 in esophageal cancer cell lines was detected. After cell transfection, the effects of miR-2053 overexpression on proliferation, apoptosis, migration and invasion of esophageal cancer cells were determined. Moreover, the potential molecular mechanism was explored by measuring the epithelial-mesenchymal transition (EMT) and apoptosis-related proteins. Luciferase reporter assay was conducted to investigate the target gene of miR-2053. The protein expressions of PI3K/AKT pathway associated factors were detected after overexpression of miR-2053 or administration with the pathway inhibitor LY294002. The miR-2053 was downregulated in esophageal cancer cell lines. Overexpression of miR-2053 inhibited cell proliferation, migration and invasion while promoted apoptosis. Molecular mechanism elucidated that miR-2053 could reduce EMT and elevate the expression of pro-apoptotic proteins. Further study found that overexpressed miR-2053 could negatively regulate KIF3C and involve in PI3K/AKT signaling pathway. Our study demonstrated the downregulation of miR-2053 in esophageal cancer. Downregulation of miR-2053 involved in the proliferation, apoptosis, migration and invasion of esophageal cancer cells through upregulating KIF3C expression and activating the PI3K/AKT signaling pathway. miR-2053 may have the potential in clinical treatment of esophageal cancer.

Relationship between cervical esophageal squamous cell carcinoma and human papilloma virus infection and gene mutations

Cervical esophageal squamous cell carcinoma (CESCC) is rare, accounting for 5% of all esophageal carcinomas. Several diagnostic and predictive markers have been studied. However, to the best of our knowledge, no biomarker is known to determine patient management except the clinical stage. The present study aimed to evaluate whether human papilloma virus (HPV) infection, epidermal growth factor receptor (EGFR) and its pathway-related gene mutations, known to be sensitive biomarkers of oropharyngeal carcinomas, could be used as biomarkers for the prediction of the prognosis of patients with CESCC. The present retrospective study included patients with CESCC who received chemoradiotherapy or surgery. HPV infection and the genomic status of EGFR, KRAS, BRAF, NRAS and PIK3CA of each tumor sample from patients with CESCC were analyzed by in situ hybridizations (ISH) and PCR methods, respectively. The present study included 33 patients with CESCC (male/female, 29/4; median age, 62 years; age range, 41-86 years; clinical stage I/II/III/IV, 2/6/10/15). The present study detected HPV in one patient (3.0%) by ISH and PCR. Concerning the investigation of EGFR and its pathway-related gene mutations, the present study detected 15.1% of EGFR, 6.0% of NRAS, 3.5% of BRAF, 3.0% of KRAS and 3.0% for PIK3CA mutations, with no significant relationship between any gene mutations and the clinical prognostic factors. The HPV-infected patient did not exhibit any gene mutations. The present study indicated that HPV infection, EGFR and its pathway-related gene mutations rarely exist in patients with CESCC. The relationship between these biomarkers and the prognosis in patients with CESCC is still unclear.

Molecular and in-silico analysis of single nucleotide polymorphism targeting human TP53 gene exon 5-8 in Sudanese esophageal cancer patients

Background: The protein product of the normal TP53 gene performs an essential function in cell cycle control and tumor suppression, and the mutation of a TP53 gene is an essential step in the development of many cancers. Despite the reported association of TP53 gene mutations with many human cancers, the comprehensive computational analysis of single nucleotide polymorphisms (SNPs), and their functional impacts, still remains rare. Methods: In this study DNA were extracted from formalin fixed paraffin embedded samples followed by the conventional polymerase chain reaction and DNA sequencing. Computational analysis was performed using different algorithms to screen for deleterious SNPs. Results: The results demonstrate that there are synonymous SNPs (sSNPs) and non-synonymous SNPs (nsSNPs) in the TP53 gene that may be deleterious to p53 structure and function. Additionally, TP53 gene mutations were found in 40% of samples. Six out of ten of TP53 gene mutations occurred in exon 5, two mutation in exon 6 and other two were present in exon 8. Only one SNP in position E298Q was predicted to have a neutral effect and other SNPs were predicted to be disease related according to Mutation Taster software. A total of 37.2% of squamous cell carcinoma (SCC) samples were found to be mutated, 87.5% of them exist in exon 5, 12.5% in exon 6 and 6.3% in exon 8, whereas adenocarcinoma (AC) achieved a higher rate of mutation (57.1%) with 100% exon 5 involvement. Conclusions: Mutation of TP53 exon 5 in esophageal cancer patients were the most frequent. Genomic results have identified a higher TP53 mutation rate in esophageal AC in contrast to SCC.

p63-Dependent Dickkopf3 Expression Promotes Esophageal Cancer Cell Proliferation via CKAP4

Dickkopf3 (DKK3) is a secretory protein that belongs to the DKK family, but exhibits structural divergence from other family members, and its corresponding receptors remain to be identified. Although DKK3 has been shown to have oncogenic functions in certain cancer types, the underlying mechanism by which DKK3 promotes tumorigenesis remains to be clarified. We show here that DKK3 stimulates esophageal cancer cell proliferation via cytoskeleton-associated protein 4 (CKAP4), which acts as a receptor for DKK3. DKK3 was expressed in approximately 50% of tumor lesions of esophageal squamous cell carcinoma (ESCC) cases; simultaneous expression of DKK3 and CKAP4 was associated with poor prognosis. Anti-CKAP4 antibody inhibited both binding of DKK3 to CKAP4 and xenograft tumor formation induced by ESCC cells. p63, a p53-related transcriptional factor frequently amplified in ESCC, bound to the upstream region of the DKK3 gene. Knockdown of p63 decreased DKK3 expression in ESCC cells, and reexpression of DKK3 partially rescued cell proliferation in p63-depleted ESCC cells. Expression of ΔNp63α and DKK3 increased the size of tumor-like esophageal organoids, and anti-CKAP4 antibody inhibited growth of esophageal organoids. Taken together, these results suggest that the DKK3-CKAP4 axis might serve as a novel molecular target for ESCC.Significance: In esophageal cancer, findings identify DKK3 as a poor prognostic indicator and demonstrate CKAP4 inhibition as an effective therapeutic strategy. Cancer Res; 78(21); 6107-20. ©2018 AACR.

The African Esophageal Cancer Consortium: A Call to Action

Esophageal cancer is the eighth most common cancer worldwide and the sixth most common cause of cancer-related death; however, worldwide incidence and mortality rates do not reflect the geographic variations in the occurrence of this disease. In recent years, increased attention has been focused on the high incidence of esophageal squamous cell carcinoma (ESCC) throughout the eastern corridor of Africa, extending from Ethiopia to South Africa. Nascent investigations are underway at a number of sites throughout the region in an effort to improve our understanding of the etiology behind the high incidence of ESCC in this region. In 2017, these sites established the African Esophageal Cancer Consortium. Here, we summarize the priorities of this newly established consortium: to implement coordinated multisite investigations into etiology and identify targets for primary prevention; to address the impact of the clinical burden of ESCC via capacity building and shared resources in treatment and palliative care; and to heighten awareness of ESCC among physicians, at-risk populations, policy makers, and funding agencies.

Esophageal carcinosarcoma comprised of minimally invasive squamous cell carcinoma and undifferentiated pleomorphic sarcoma: A collision cancer?

Esophageal carcinosarcoma is a rare neoplasm with components of squamous cell carcinoma and sarcomatous spindle cell stroma. The latter may show overt mesenchymal differentiation but is thought to be derived from carcinoma cells in most cases. Here, we report a case of esophageal carcinosarcoma that appeared to be comprised of different origins of epithelial and mesenchymal tumor cells. The sarcomatous component formed an intralumial pedunculated large mass lesion that consisted of pleomorphic atypical histiocyte-like cells. The squamous epithelium exhibited features of mostly dysplasia with minor foci of microinvasive squamous cell carcinoma. The invasive carcinoma was apart from the sarcoma, and no transitions were observed between the epithelial and sarcomatous cells. Immunohistochemistry showed that the sarcoma cells did not express any lineage-specific markers, including those for epithelial cells and histiocytes, which lead to the diagnosis of undifferentiated pleomorphic sarcoma. Although cyclin D1 was overexpressed in the carcinoma cells, it was nearly negative in the sarcoma cells. These findings indicate that the tumor may be a collision carcinosarcoma. It is highly likely that the patient's history of heavy smoking and alcohol consumption were relevant to the pathogenesis, at least for the epithelial component, of the tumor.

P53 Gene Mutations in Surgical Margins and Primary Tumor Tissues of Patients with Squamous Cell Carcinoma of the Head and Neck

Aims and Background

The frequency of p53 mutations in primary tumors, the effect of the mutations on some clinical and pathological features of head and neck squamous cell carcinoma, and the impact of p53 mutations in the surgical margins on local recurrence were determined.

Material and Methods

We investigated the presence of p53 mutations in primary tumor samples and in the surgical margins of 34 patients with head and neck cancer using single strand conformational polymorphism and sequencing analysis.

Results

The p53 mutations (codons 175addAT, 175delGC, 206G→A, and 248delC) were found in the primary tumor samples of 15 of 34 patients (44.12%) and in the surgical margins of 5 of the 15 tumors (33.33%) with p53 mutations.

Conclusions

We found no statistically significant association between the presence of p53 mutations in the primary tumor, the clinical and pathological features, or outcome of head and neck squamous cell carcinoma in this study. Furthermore, the presence of p53 mutations in the surgical margins may not increase the risk of local-regional recurrence, but probably increases the risk of developing distant metastases or second primary tumors.

RHCG Suppresses Tumorigenicity and Metastasis in Esophageal Squamous Cell Carcinoma via Inhibiting NF-κB Signaling and MMP1 Expression

Background and Aims: Esophageal squamous cell carcinoma (ESCC), a major histologic subtype of esophageal cancer, is increasing in incidence, but the genetic underpinnings of this disease remain unexplored. The aim of this study is to identify the recurrent genetic changes, elucidate their roles and discover new biomarkers for improving clinical management of ESCC. Methods: Western blotting and immunohistochemistry were performed to detect the expression level of RHCG. Bisulfite genomic sequencing (BGS) and methylation-specific PCR (MSP) were used to study the methylation status in the promoter region of RHCG. The tumor-suppressive effect of RHCG was determined by both in-vitro and in-vivo assays. Affymetrix cDNA microarray was used to identify the underlying molecular mechanism. Results:RHCG was frequently downregulated in ESCCs, which was significantly correlated with poor differentiation (P = 0.001), invasion (P = 0.003), lymph node metastasis (P = 0.038) and poorer prognosis (P < 0.001). Demethylation treatment and bisulfite genomic sequencing analyses revealed that the downregulation of RHCG in both ESCC cell lines and clinical samples was associated with its promoter hypermethylation. Functional assays demonstrated that RHCG could inhibit clonogenicity, cell motility, tumor formation and metastasis in mice. Further study revealed that RHCG could stabilize IκB by decreasing its phosphorylation, and subsequently inhibit NF-κB/p65 activation by blocking the nuclear translocation of p65, where it acted as a transcription regulator for the upregulation of MMP1 expression. Conclusions: Our results support the notion that RHCG is a novel tumor suppressor gene that plays an important role in the development and progression of ESCC.

Genomic analysis of oesophageal squamous-cell carcinoma identifies alcohol drinking-related mutation signature and genomic alterations

Approximately half of the world's 500,000 new oesophageal squamous-cell carcinoma (ESCC) cases each year occur in China. Here, we show whole-genome sequencing of DNA and RNA in 94 Chinese individuals with ESCC. We identify six mutational signatures (E1-E6), and Signature E4 is unique in ESCC linked to alcohol intake and genetic variants in alcohol-metabolizing enzymes. We discover significantly recurrent mutations in 20 protein-coding genes, 4 long non-coding RNAs and 10 untranslational regions. Functional analyses show six genes that have recurrent copy-number variants in three squamous-cell carcinomas (oesophageal, head and neck and lung) significantly promote cancer cell proliferation, migration and invasion. The most frequently affected genes by structural variation are LRP1B and TTC28. The aberrant cell cycle and PI3K-AKT pathways seem critical in ESCC. These results establish a comprehensive genomic landscape of ESCC and provide potential targets for precision treatment and prevention of the cancer.

Expression of methylation-modulated tumor-related genes in endoscopically resected early esophageal squamous neoplasia

Smoking and alcohol consumption are major risk factors for the development of esophageal squamous cell carcinoma (ESCC). Recent studies have demonstrated that smoking and alcohol consumption may be associated with altered DNA methylation in human cancer development. The aim of the present study was to evaluate methylation-modulated protein expression of tumor-related genes (TRGs) in the early stages of esophageal squamous neoplasia (ESN). ESN tissue samples (n=141) comprising 19 cases of low-grade intraepithelial neoplasia (LGIN), 70 of high-grade intraepithelial neoplasia/carcinoma in situ (HGIN/CIS) and 52 of invasive cancer, were endoscopically resected. The methylation-modulated protein expression of 5 TRGs [fragile histidine triad (FHIT), E-cadherin, MutL homolog 1 (MLH1) /MutS homolog 2 (MSH2) and cyclooxygenase-2 (COX-2)] as well as p53 was examined with immunohistochemistry, and their expression was compared with patient clinicopathological characteristics. Reduced or loss of FHIT, E-cadherin, MLH1/MSH2 and COX-2 expression was detected in 26.3 (5/19), 5.3 (1/19), 0 (0/19) and 63.2% (12/19) of LGIN cases, 61.4 (43/70), 18.6 (13/70), 7.1 (5/70) and 65.7% (46/70) of HGIN/CIS cases, and 78.8 (41/52), 50.0 (26/52), 11.5 (6/52) and 59.6% (31/52) of invasive cancer cases, respectively. Reduced or absent expression of FHIT and E-cadherin was significantly associated with neoplastic progression (FHIT, P=0.0007; E-cadherin, P=0.00014). The mean number of TRGs (FHIT, E-cadherin, MLH1/MSH2, and COX-2) that exhibited reduced or absent expression in LGIN, HGIN/CIS and invasive cancer specimens was 1.12±0.61, 1.66±0.93 and 2.09±0.96, respectively, demonstrating a significant stepwise increment from LGIN to HGIN/CIS and then to invasive cancer (P<0.05). p53 overexpression was frequently detected in ESN with head and neck carcinomas. However p53 overexpression was not significantly associated with ESN progression. An increase in the number of the 5 TRG proteins with reduced or loss of expression in the early stages of esophageal tumorigenesis was demonstrated, and their decreased expression was observed to be associated with tumor progression. Therefore, smoking and alcohol drinking may be associated with not only carcinogenesis but also the progression of ESN.

miR-195 Regulates Proliferation and Apoptosis through Inhibiting the mTOR/p70s6k Signaling Pathway by Targeting HMGA2 in Esophageal Carcinoma Cells

miR-195 is related to tumorigenesis and frequently inhibits cell proliferation and promotes apoptosis in various cancers, including esophageal carcinoma (EC). The mTOR/p70s6k signaling pathway, which is the major target pathway for HMGA2, regulates the survival and cell proliferation of many tumors and is commonly active in EC. The relationships of miR-195, HMGA2, and the mTOR/p70s6k signaling pathway in EC, however, remain unknown. In the present study, we found that the miR-195 level was significantly downregulated in EC tissues, while the mRNA expressions of HMGA2 were significantly upregulated. Dual-luciferase reporter assay demonstrated that HMGA2 is a target of miR-195. MTT assay and flow cytometry revealed that miR-195 overexpression inhibited cell proliferation and induced apoptosis by targeting HMGA2. We also found that HMGA2 restored the inhibitory effect of miR-195 on phosphorylation of mTOR and p70S6K. Furthermore, rapamycin, a specific inhibitor of the mTOR/p70S6K signaling pathway, decreased the levels of Ki-67 and Bcl-2/Bax ratio, inhibited cell proliferation, and promoted apoptosis in EC cells. In conclusion, upregulation of miR-195 significantly suppressed cell growth and induced apoptosis of EC cells via suppressing the mTOR/p70s6k signaling pathway by targeting HMGA2.

Long non-coding RNA LINC00672 contributes to p53 protein-mediated gene suppression and promotes endometrial cancer chemosensitivity

Thousands of long intergenic non-protein coding RNAs (lincRNAs) have been identified in mammals in genome-wide sequencing studies. Some of these RNAs have been consistently conserved during the evolution of species and could presumably function in important biologic processes. Therefore, we measured the levels of 26 highly conserved lincRNAs in a total of 176 pairs of endometrial carcinoma (EC) and surrounding non-tumor tissues of two distinct Chinese populations. Here, we report that a lincRNA, LINC00672, which possesses an ultra-conserved region, is aberrantly down-regulated during the development of EC. Nevertheless, LINC00672 is a p53-targeting lincRNA acting along with heterogeneous nuclear ribonucleoproteins as a suppressive cofactor, which locally reinforces p53-mediated suppression of LASP1, an evolutionarily conserved neighboring gene of LINC00672 and putatively associated with increased tumor aggressiveness, during anti-tumor processes. LINC00672 overexpression could lower the levels of LASP1 and slow the development of malignant phenotypes of EC both in vitro and in vivo Moreover, LINC00672 significantly increased the 50% inhibitory concentration of paclitaxel in EC cells and increased the sensitivity of xenograft mice to paclitaxel. These findings indicate that LINC00672 can influence LASP1 expression as a locus-restricted cofactor for p53-mediated gene suppression, thus impacting EC malignancies and chemosensitivity to paclitaxel.

Prognostic significance of beta-catenin expression in patients with esophageal carcinoma: a meta-analysis

Many studies have reported β-catenin involvement in the development of esophageal carcinoma (EC), but its prognostic significance for EC patients remains controversial. Therefore, we conducted this meta-analysis to explore the issue in detail. After searching PubMed, EMBASE, Web of Science, and Chinese Biomedical Literature Database, we included a total of ten relevant studies. We pooled the overall survival (OS) data using RevMan 5.2 software. The results showed that aberrant expression of β-catenin was associated with a significant increase of mortality risk (hazard ratio 1.71, 95%CI 1.46-2.01; p<0.00001). Subgroup analyses further suggested that aberrant expression of β-catenin resulted in poor OS of EC patients regardless of histological type of EC, study location or criteria for aberrant expression of β-catenin, and the sensitivity analyses revealed that the result was robust. The meta-analysis revealed that aberrant expression of β-catenin could be a predicative factor of poor prognosis for EC patients.

Concurrent radiotherapy with gefitinib in elderly patients with esophageal squamous cell carcinoma: Preliminary results of a phase II study

The survival rate associated with esophageal cancer is very poor due to diagnosis at advanced stages of disease and insensitivity to chemotherapy. This study investigated the efficacy of gefitinib combination with radiation in 20 elderly patients with esophageal squamous cell carcinoma (ESCC) who were not eligible for platinum-based chemotherapy. Immunohistochemistry was performed to analyze epidermal growth factor receptor (EGFR) expression, and the amplified refractory mutation system was used to detect EGFR mutations. Treatment response was assessed by endoscopy and computed tomography. Treatment toxicity was evaluated using the National Cancer Institute's Common Toxicity Criteria. The data showed that among these 20 patients, 5 experienced a complete response (CR), 13 a partial response (PR), and 2 had stable disease. The overall response rate (CR + PR) was 90%, the median overall survival (OS) was 14.0 months (95% confidence interval [CI]: 10.0–17.9 months), and the median progression-free survival was 7.0 months (95% CI: 0–17.2 months). Patients with good Eastern Cooperative Oncology Group performance status, never smoking, and EGFR mutated tumors had the best OS (14.0, 14.0, and 17.0 months, respectively). Treatment-related grade 3/4 toxicity occurred in five patients. No case of grade 3/4 impaired liver function or hematological toxicity was observed. Concurrent radiotherapy with gefitinib is effective and tolerable in elderly ESCC patients.

Cervical esophageal cancer: a gap in cancer knowledge

BACKGROUND

The aim of this systematic review is to provide an overview of the diagnosis, treatment options and treatment-related complications of cervical esophageal carcinoma (CEC) and to subsequently provide recommendations to improve quality of care.

DESIGN

Studies were identified in PubMed, EMBASE and Web of Science. A total of 107 publications fulfilled the inclusion criteria and were included.

RESULTS

CEC is uncommon, accounting for 2%-10% of all esophageal carcinomas. These tumors are often locally advanced at presentation and have a poor prognosis, with a 5-year overall survival of 30%. Tobacco and alcohol consumption seem to be the major risk factors for developing CEC. Surgery is usually not possible due to the very close relationship to other organs such as the larynx, trachea and thyroid gland. Therefore, the current standard of care is definitive chemoradiation (dCRT) with curative intent. Treatment regimens used to treat CEC are adapted by established regimens in lower esophageal squamous cell carcinoma and head and neck squamous cell carcinoma. However, dCRT may be accompanied by severe side-effects and complications. Several diagnostic and predictive markers have been studied, but currently, there is no other biomarker than clinical stage to determine patient management. Suggestions to improve patient outcomes are to determine the exact radiation dose needed for adequate locoregional control and to combine radiotherapy with optimal systemic therapy backbone.

CONCLUSION

CEC remains unchartered territory for many practising physicians and patients with CEC have a poor prognosis. To improve the outcome for CEC patients, future studies should focus on the identification of new diagnostic biomarkers or targets for radiosensitizers, amelioration of radiation schedules, optimal combination of chemotherapeutic agents and/or new therapeutic targets.

Long non-coding RNA-Low Expression in Tumor inhibits the invasion and metastasis of esophageal squamous cell carcinoma by regulating p53 expression

Long non-coding RNAs (lncRNAs) are involved in governing fundamental biological processes, and, in many lncRNAs, the expression level is altered and likely to have a functional role in tumorigenesis, including apoptosis, migration and invasion. The lncRNA-Low Expression in Tumor (LET), a recently identified lncRNA, was demonstrated to be downregulated in hepatocellular and gallbladder cancer. However, its role in esophageal squamous cell carcinoma (ESCC) requires investigation. The expression level of lncRNA-LET mRNA in primary ESCC and matched healthy tissues (48 cases) was determined by reverse transcription-quantitative polymerase chain reaction. In addition, the effects of lncRNA-LET on cell apoptosis were evaluated by flow cytometric analysis, the regulatory effect of lncRNA-LET on migration was detected using a wound healing assay and cellular invasion was analyzed by Matrigel-coated transwell assay. Furthermore, the effect of lncRNA-LET on cell proliferation was investigated by 5-ethynyl-2′-deoxyuridine cell proliferation assay and protein levels of lncRNA-LET targets were analyzed by western blotting. lncRNA-LET expression was decreased in primary ESCC tissues when compared with paired healthy tissues, and was identified to be associated with the clinical features. Overexpression of lncRNA-LET was observed to inhibit the migration and invasion of ESCC cells, and modulate p53 expression levels in human ESCC cell lines in vitro. These results establish that lncRNA-LET is significant in the regulation of tumor progression and metastasis, and serves as a tumor suppressor in, and therefore has therapeutic potential for, the treatment of human ESCC.

High expression of TACC3 in esophageal squamous cell carcinoma correlates with poor prognosis

To analyze the expression of the transforming acidic coiled-coil protein 3 (TACC3) in esophageal squamous cell carcinoma (ESCC) samples, and to identify whether TACC3 can serve as a biomarker for the diagnosis and prognosis of ESCC, qPCR, western blotting and immunohistochemistry staining (IHC) were utilized to detect the expression of TACC3. Furthermore, cell growth, colony formation, migration ability and the epithelial-mesenchymal transition markers of ESCC cells in which TACC3 were knocked-down were measured. The mRNA and protein levels of TACC3 were higher in ESCC specimens compared to non-tumorous esophageal epithelial tissues. IHC results revealed TACC3 expression was significantly correlated to differentiation (p = 0.017) and lymphoid nodal status (p = 0.028). The patients with high-expression of TACC3 had a significantly poor prognosis compared to those of low-expression (p = 0.017), especially in the patients at stages I–II (p = 0.028). Multivariate analysis indicated that TACC3 expression was an independent prognostic factor for ESCC patients (p = 0.025). Knockdown of TACC3 inhibited the ability of cell proliferation, colony formation and migration. This study first identifies TACC3 not only as a useful biomarker for diagnose and prognosis of ESCC, but also as a potential therapeutic target for patients with ESCC.

Association Between Smoking and p53 Mutation in Oesophageal Squamous Cell Carcinoma: A Meta-analysis

AIMS

Several studies have evaluated the association between smoking and p53 mutation in oesophageal squamous cell carcinoma (ESCC), but the conclusions are inconsistent. The aim of the present study was to carry out a meta-analysis evaluating the relationship between smoking and p53 mutation in patients with ESCC.

MATERIALS AND METHODS

Eligible studies were identified through searches in PubMed and EMBASE. The odds ratio with 95% confidence interval was used to assess the association. In total, 20 studies were identified that met the selection criteria; these studies were analysed using STATA 12.0 software.

RESULTS

The 20 studies identified comprised 1524 ESCC patients, of whom 72.97% were smokers and 27.03% were non-smokers. The pooled odds ratio of p53 mutation in ESCC for any cigarette smoking versus no smoking was 1.28 (95% confidence interval=0.88-1.88). The estimated odds ratios were 1.06 (95% confidence interval=0.56-2.00, based on five studies, 129 light smokers and 70 non-smokers) for light smoking and 2.01 (95% confidence interval=1.12-3.60, based on five studies, 223 heavy smokers and 73 non-smokers) for heavy smoking.

CONCLUSION

The results of our meta-analysis indicate an overall positive relationship between heavy smoking and p53 mutation in ESCC. Heavy smokers with ESCC have a higher risk for p53 mutation than non-smokers. Large-scale clinical studies are still needed to draw a more precise conclusion.

Genetic features of metachronous esophageal cancer developed in Hodgkin's lymphoma or breast cancer long-term survivors: an exploratory study

Background

Development of novel therapeutic drugs and regimens for cancer treatment has led to improvements in patient long-term survival. This success has, however, been accompanied by the increased occurrence of second primary cancers. Indeed, patients who received regional radiotherapy for Hodgkin’s Lymphoma (HL) or breast cancer may develop, many years later, a solid metachronous tumor in the irradiated field. Despite extensive epidemiological studies, little information is available on the genetic changes involved in the pathogenesis of these solid therapy-related neoplasms.

Methods

Using microsatellite markers located in 7 chromosomal regions frequently deleted in sporadic esophageal cancer, we investigated loss of heterozygosity (LOH) and microsatellite instability (MSI) in 46 paired (normal and tumor) samples. Twenty samples were of esophageal carcinoma developed in HL or breast cancer long-term survivors: 14 squamous cell carcinomas (ESCC) and 6 adenocarcinomas (EADC), while 26 samples, used as control, were of sporadic esophageal cancer (15 ESCC and 11 EADC).

Results

We found that, though the overall LOH frequency at the studied chromosomal regions was similar among metachronous and sporadic tumors, the latter exhibited a statistically different higher LOH frequency at 17q21.31 (p = 0.018). By stratifying for tumor histotype we observed that LOH at 3p24.1, 5q11.2 and 9p21.3 were more frequent in ESCC than in EADC suggesting a different role of the genetic determinants located nearby these regions in the development of the two esophageal cancer histotypes.

Conclusions

Altogether, our results strengthen the genetic diversity among ESCC and EADC whether they occurred spontaneously or after therapeutic treatments. The presence of histotype-specific alterations in esophageal carcinoma arisen in HL or breast cancer long-term survivors suggests that their transformation process, though the putative different etiological origin, may retrace sporadic ESCC and EADC carcinogenesis.

Enhancement of silencing DNA polymerase β on the radiotherapeutic sensitivity of human esophageal carcinoma cell lines

Human DNA polymerase β (DNA polymeraseβ (polβ)) is a small monomeric protein which is essential for short-patch base excision repair (BER). It plays an important role in regulating the radiation sensitivity of tumor cells in the course of tumor radiation therapy. In this study, qRT-PCR and Western blot assays were used to quantify polβ expression levels in esophageal carcinoma (EC) cells that were transfected with polβ small interfering RNA (siRNA). Cell counting Kit-8 (CCK-8), flow cytometry, and Hoechst/PI stain assays were conducted to evaluate the effects of silencing polβ on the radiotherapeutic sensitivity of EC cells. We found that the expression levels of polβ in EC cells were significantly decreased after transfection with polβ siRNA. Then, we found that polβ silencing increased the sensitivity of EC cells to radiation therapy. In conclusion, our study paves the way for a better understanding of the mechanism of the polβ gene in DNA repair, and we propose that RNA interference technology will have important applications in gene therapy of EC and other cancers in the future.

Increased levels of the long intergenic non-protein coding RNA POU3F3 promote DNA methylation in esophageal squamous cell carcinoma cells

BACKGROUND & AIMS

Thousands of long intergenic non-protein coding RNAs (lincRNAs) have been identified in mammals via genome-wide sequencing studies. Many are functional, but are expressed aberrantly by cancer cells. We investigated whether levels of lincRNAs are altered during the development of esophageal squamous cell carcinoma (ESCC).

METHODS

We used quantitative real-time polymerase chain reaction to measure levels of 26 highly conserved lincRNAs in ESCC and surrounding nontumor tissues. A total of 182 ESCC and paired adjacent nontumor tissue samples were collected from patients undergoing tylectomy at The First Affiliate Hospital of Soochow University from 2001 through 2009; another 178 ESCC tissue pairs were collected from Guangzhou Medical University from 2002 through 2009. LincRNAs were expressed from lentiviral vectors or knocked down with small hairpin RNAs in Eca-109 and TE-1 cells.

RESULTS

Levels of a lincRNA encoded by a gene located next to POU3F3 (linc-POU3F3) were significantly higher in ESCC than neighboring nontumor tissues. In RNA immunoprecipitation assays, linc-POU3F3 was associated with the EZH2 messenger RNA (mRNA). Overexpression of linc-POU3F3 in cell lines increased their proliferation and ability to form colonies, and reduced the expression of POU3F3 mRNA, whereas knockdown of linc-POU3F3 increased the levels of POU3F3 mRNA. CpG islands in POU3F3 were densely hypermethylated in cell lines that overexpressed linc-POU3F3; methylation at these sites was reduced by knockdown of linc-POU3F3. Pharmacologic inhibition of EZH2 increased the levels of POU3F3 mRNA and significantly reduced binding of DNA methyltransferase (DNMT)1, DNMT3A, and DNMT3B to POU3F3. ESCC cells with knockdown of linc-POU3F3 formed xenograft tumors more slowly in mice than control ESCC cells.

CONCLUSIONS

Levels of linc-POU3F3 are increased in ESCC samples from patients compared with nontumor tissues. This noncoding RNA contributes to the development of ESCC by interacting with EZH2 to promote methylation of POU3F3, which encodes a transcription factor.

The tumor suppressor LKB1 antagonizes WNT signaling pathway through modulating GSK3β activity in cell growth of esophageal carcinoma

The tumor suppressor LKB1 gene encodes a serine-threonine kinase that regulates cell proliferation and polarity. Inactivation of LKB1 by mutations in LKB1 or loss of its expression is highly correlated with lung, ovarian, and pancreatic cancers, and WNT/β-catenin pathway is also known to be involved in many human malignancies. However, the relationship between LKB1 and WNT signaling pathway in esophageal carcinoma remains unknown. The expression of LKB1 in 62 cases of esophageal cancer patients was determined by quantitative real-time PCR. It was found that LKB1 mRNA level was significantly lower than the adjacent normal epithelium and that the LKB1 downregulation was correlating with TNM stages. Moreover, the expression of WNT target genes such as Cyclin D1, C-MYC, MMP2, and FZD2 was significantly upregulated in esophageal cancer tissues. LKB1 overexpression in TE10 cells inhibited TOPFlash luciferase reporter activity and WNT target gene expression even in the presence of WNT3A. Conversely, LKB1 knockdown enhanced WNT signaling activity in esophageal cancer cells. It was also found that LKB1 antagonized WNT signaling pathway through interaction with GSK3β to downregulate β-catenin expression level. Functional investigation revealed that LKB1 suppressed the promotion effects of WNT3A on the cell growth of TE10 cells. The LKB1 functions in regulating cell growth and WNT target genes expression were impaired by GSK3β inhibition, suggesting that LKB1 antagonized WNT-induced cell proliferation through enhancement of GSK3β activity. Together, the interaction between LKB1 and GSK3β upregulates GSK3β activity to suppress WNT-induced cell proliferation in esophageal carcinoma cells. Loss of LKB1 expression may result in the deregulation of WNT/β-catenin pathway to promote malignant progression of esophageal cancer.

Single nucleotide polymorphism at alcohol dehydrogenase-1B is associated with risk of esophageal squamous cell carcinoma

Background

Esophageal squamous incidence in many developed countries has increased dramatically over last decades, while the underlying mechanism of the biogenesis of ES was still unknown.

Methods

Here, we investigate 1001 subjects with esophageal cancer recruited from the affiliated hospital of Shanghai Jiao Tong University from Jan. 1, 2001 to Feb. 2, 2004. Single nucleotide polymorphism (SNP) of alcohol dehydrogenase-1B (ADH1B) was performed, and the recombinant plasimd containing ADH1B was constructed. Then, the ADH1B was purified and the enzymatic activity was assayed according to the methodology of Quayle. Furthermore, the effect of ADH1B on proliferation of human esophageal squamous cell lines was determined and the underlying mechanism of ADH1B was investigated.

Results

Logistic regression analyses revealed that subjects carrying the GG variant homozygote had a significant 2.81-fold (adjusted OR = 2.81; 95% CI = 2.18-3.62) increased risk of esophageal cancer. We found that SNP of ADH1B (GG) significantly promotes cell proliferation in ESGG. ADH1B (GG) could down-regulate endogenous ADH1B expression at posttranscriptional level. Moreover, re-expression of ADH1B in cells transfected with ADH1B (AA) significantly inhibits cell proliferation.

Conclusions

Our data implied that ADH1B (GG) could promote cell proliferation in human ESGG through regulating the enzyme activity of ADH1B. Therefore, we propose that ADH1B might be used as a therapeutic agent for human ESGG.

Effect of PTEN antisense oligonucleotide on oesophageal squamous cell carcinoma cell lines

OBJECTIVE

To investigate the effects of a phosphatase and tensin homologue (PTEN) antisense oligonucleotide on PTEN and mammalian target of rapamycin (mTOR) mRNA and protein, cell proliferation and apoptosis in oesophageal squamous cell carcinoma (OCSS) cell lines.

METHODS

EC9706 and EC1 cells were transfected with PTEN antisense oligonucleotide, sense oligonucleotide or nonsense oligonucleotide. Cell proliferation and apoptosis were quantified. Immuno cyto chemistry and in situ hybridization were used to determine PTEN and mTOR protein and mRNA levels, respectively.

RESULTS

Transfection with PTEN antisense oligonucleotide dose- and time-dependently enhanced cell proliferation and inhibited apoptosis in both EC9706 and EC1 cells. PTEN mRNA and protein were significantly downregulated, and mTOR protein and mRNA were significantly upregulated.

CONCLUSION

These data suggest that PTEN is an important tumour suppressor gene in the development of OSCC.

Incidence of second primary malignancies in patients with esophageal cancer: a comprehensive review

BACKGROUND

Development of a second primary malignancy (SPM) after an index esophageal cancer is fairly rare, primarily due to decreased survival in patients with esophageal cancer. However, with advances in early detection and therapy, the number of long-term survivors is increasing, as is the incidence of SPMs in this population.

SCOPE

We review herein the published literature on the incidence of SPMs after an index esophageal cancer as well as its associated risk factors, prognosis and surveillance. We discuss predisposing factors that may contribute to the development of SPMs, epidemiology and attempts at chemoprevention.

FINDINGS

Data from population-based studies, retrospective reviews and case reports indicate an increased risk of SPMs in patients with esophageal cancer with reported incidence rates between 8.3 and 27.1%. Index esophageal squamous cell carcinomas have a higher association with other tobacco-related cancers such as those of the head and neck and lung. They have also shown an association with second primary cancers of the breast, stomach, thyroid, and kidney. Individuals with esophageal adenocarcinomas are at a higher risk of developing second cancers of the stomach, oropharynx and lung/bronchus. Other primary cancer sites involved include the kidney, colorectum and pancreas. Common risk factors including lifestyle and genetic alterations may explain the increased incidence of second primary cancers in this patient population.

CONCLUSIONS

Risk of developing a second malignancy should be anticipated after curative treatment of esophageal cancer, and raises concerns for optimal surveillance and therapy of these patients. Recent literature suggests similar survival rates in esophageal cancer patients with and without SPMs. With the increasing incidence of SPMs in subjects with esophageal cancer, there may be benefit to close screening for and aggressive therapy of SPMs. However, further studies are needed to elucidate optimal management strategies.

RNAi targeting CXCR4 inhibits proliferation and invasion of esophageal carcinoma cells

CXC chemokine receptor 4 was found to be expressed by many different types of human cancers and its expression has been correlated with tumor aggressiveness, poor prognosis and resistance to chemotherapy. However the effect of CXCR4 on the esophageal carcinoma cells remains unclear, the present study explored the effects of CXCR4 siRNA on proliferation and invasion of esophageal carcinoma KYSE-150 and TE-13 cells. Two siRNA sequence targeting CXCR4 gene were constructed and then were transfected into KYSE-150 and TE-13 cells by Lipofectamine™2000. Changes of CXCR4 mRNA and protein were analyzed by qRT-PCR and Western blot. Effect of CXCR4 siRNA on KYSE-150 and TE-13 cells proliferation was determined by MTT. Transwell invasion assay was used to evaluate the invasion and metastasis of KYSE-150 and TE-13 cells. Tumor growth was assessed by subcutaneous inoculation of cells into BALB/c nude mice. qRT-PCR and Western blot demonstrate that the expression level of CXCR4 gene were obviously decreased in KYSE-150 and TE-13 cells transfected with CXCR4 targeting siRNA expression vectors. The average amount of cells transfected with CXCR4 siRNA penetrating Matrigel was significantly decreased (p<0.05). Injection of CXCR4 siRNA transfected cells inhibited tumor growth in a xenograft model compared with blank and negative control groups (p <0.05). CXCR4 silenced by siRNA could suppress the proliferation, invasion and metastasis of esophageal carcinoma cell lines KYSE-150 and TE-13 in vitro and in vivo. The results provide a theoretical and experimental basis for the gene therapy of ESCC using RNAi technology based on CXCR4 target site.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/3502376691001138.

Epidermal growth factor receptor (EGFR) mutations and expression in squamous cell carcinoma of the esophagus in central Asia

Background

Esophageal squamous cell carcinoma (ESCC) shows geographic variations in incidence, with high incidences (>50/10⁵ person-years) in central Asia, including North Eastern Iran (Golestan) and Northern India (Kashmir). In contrast to Western countries, smoking does not appear to be a significant risk factor for ESCC in central Asia. In lung adenocarcinoma, activating mutations in the gene encoding epidermal growth factor receptor (EGFR) are frequent in tumors of never smokers of Asian origin, predicting therapeutic sensitivity to Egfr-targeting drugs.

Methods

In this study 152 cases of histologically confirmed ESCC from Iran (Tehran and Golestan Province) and North India (Kashmir Valley) have been analyzed for EGFR mutation by direct sequencing of exons 18–21. Egfr protein expression was evaluated by immunohistochemistry in 34 samples from Tehran and HER2 mutations were analyzed in 54 cases from Kashmir.

Results

A total of 14 (9.2%) EGFR variations were detected, including seven variations in exons. Among those, four (2.6%) were already documented in lung cancers, two were reported as polymorphisms and one was a potentially new activating mutation. All but one variation in introns were previously identified as polymorphisms. Over-expression of Egfr was detected in 22/34 (65%) of tested cases whereas no HER2 mutation was found in 54 cases from Kashmir.

Conclusion

Overall, EGFR mutations appear to be a rare event in ESCC in high incidence areas of central Asia, although a very small proportion of cases may harbor mutations predicting sensitivity to anti-Egfr drugs.

The cluster of miR-143 and miR-145 affects the risk for esophageal squamous cell carcinoma through co-regulating fascin homolog 1

MicroRNAs (miRNAs), 18–24 nt non-coding RNAs, are thought to play important roles in cell proliferation, differentiation, apoptosis, and development. Recent studies suggest that some of the known microRNAs map to a single genomic locale within a single polycistronic transcript. But the roles of the cluster remain to be known. In order to understand the role and mechanism of a cluster of miR-143 and miR-145 in esophageal squamous cell carcinoma (ESCC), the association of mature miR-143 and miR-145 expression with the risk for esophageal cancer was evaluated in ESCC patients with a case-control study, and target protein regulated by mature miRNA was analyzed in ESCC cell lines with 3′UTR luciferase reporter assay. The expression levels of miR-143 and miR-145 were determined in 110 pairs of esophageal cancer tissues and adjacent normal tissues using real-time reverse transcription PCR. The relative expression of miR-143 and miR-145 were statistically different between cancer tissues and matched controls. The combined expression of miR-143 and miR-145 was significantly associated with the risk for esophageal cancer. Meanwhile, the reduced expression of two miRNAs in tumor patient was supposed to have a trend of lymph node metastases. The co-expression pattern of miR-143 and miR-145 was analyzed with Pearson correlation. It showed a significant correlation between these two miRNAs expression both in tissues and tumor cell lines. 3′UTR luciferase reporter assay indicated that Fascin Homolog 1 (FSCN1) could be co-regulated by miR-143 and miR-145. The protein level of FSCN1 showed no significant linear correlation with miR-143 and miR-145 expression in ESCC cell lines with Western blotting analysis. In conclusion, since miR-143 and miR-145 could regulate oncogenic FSCN1 and take part in the modulation of metastases, the result suggested the combination variable of miR-143 and miR-145 as a potential biomarker for earlier diagnosis and prognosis of esophageal cancer.

Study on RIZ1 gene promoter methylation status in human esophageal squamous cell carcinoma

AIM: To investigate the promoter region methylation status of retinoblastoma protein-interacting zinc finger gene 1 (RIZ1) in the human esophageal squamous cell carcinoma (ESCC) cell lines and tissues and verify the relationship between methylation of RIZ1 and oncogenesis, tumor progression and metastasis etc of ESCC.

METHODS: Methylation-specific polymerase chain reaction (MSP) was used to investigate the promoter region methylation status of RIZ1 in 6 ESCC cell lines. One cell line where RIZ1 promoter region methylation was detected was selected for the next study, where the cell line was treated with 5-aza-CdR. Real-time polymerase chain reaction was used to investigate its influence on the transcription of RIZ1. Experiments using frozen pathological specimens from 47 ESCC patients were performed using the same MSP methodology.

RESULTS: Promoter methylation of RIZ1 gene was detected in TE13, CaEs17 and EC109 cell lines and the cell line TE13 was chosen for further study. The expression of RIZ1 mRNA in TE-13 was up-regulated after treatment with 5-aza-CdR. The rate of methylation in carcinomas tissues was significantly higher than those in matched neighboring normal and distal ending normal tissue, and the deviation of data was statistically significant (χ² = 24.136, P < 0.01). Analysis of the gender, age familial history, tumour deviation, tumour saturation, lymph gland displacement and clinical staging of 47 samples from ESCC patients showed that the fluctuation of data was not statistically significant.

CONCLUSION: Promoter methylation may play an important role in the epigenetic silencing of RIZ1 gene expression in human ESCC. RIZ1 is considered to be a potential tumor suppressor gene and may be a biological parameter for testing early stage human ESCC.

A small interfering RNA targeting NF-κB p65 alone or combined with 5-FU inhibits growth of esophageal squamous cell carcinoma in nude mice

NF-κB signaling pathway plays an important role in carcinogenesis. Although constitutive NF-κB activation has been reported in many human tumors, the effect of NF-κB signaling pathway in esophageal squamous cell carcinoma (ESCC) is still poorly understood. To explore the role of NF-κB signaling pathway in ESCC, RNA interference (RNAi) was used to knockdown the NF-κB p65 protein level in the ESCC cells and nude mice. 5-FU was used to investigate whether knockdown NF-κB p65 can potentiate 5-FU's antitumor effect. Animal results indicated that tumor growth was inhibited in p65 siRNA and p65 siRNA+5-FU groups as compared with the control group. Immunohistochemistry, RT-PCR and TUNEL assay showed that p65 siRNA downregulated the expression of p65 and enhanced the sensitivity of EC9706 cells to 5-FU treatment in vivo. Overall, our work indicates that downregulation of p65 can increase tumor apoptosis and potentiates the effects of 5-FU by suppressing NF-κB signaling pathway. Thus, p65 is an interesting target for ESCC treatment.

Role of p53 and p73 genes polymorphisms in susceptibility to esophageal cancer: a case control study in a northern Indian population

Genetic variants in p53 and in its homologue p73 may modulate Esophageal Cancer (EC) risk because they are supposed to influence cell cycle progression, apoptosis and DNA repair. Therefore, we aimed to evaluate the association of p53 intron3 16 bp duplication and p73 G4C14-to-A4T14 polymorphisms with susceptibility to EC in a northern Indian population in 255 EC patients and 255 age and sex matched healthy controls. We found that p53 intron3 16 bp duplication polymorphism was not associated with EC and its clinical characteristics. However, p73 G4C14-to-A4T14 polymorphism was associated with significant higher risk of EC (OR = 1.74, 95% CI = 1.16-2.60, P = 0.007) in an allele dose-dependent manner (P(trend) = 0.0047). Stratification of subjects on the basis of clinical characteristics showed that p73 AT genotype carriers were at significant increased risk of developing esophageal squamous cell carcinoma (OR = 1.78, 95% CI = 1.18-2.67, P = 0.006) at middle third tumor location (OR = 1.87, 95% CI = 1.18-2.97, P = 0.007) with lymph node metastasis (OR = 1.77, 95% CI = 1.04-3.02, P = 0.035). No interaction with environmental risk factors was observed with any of the studied polymorphisms. In summary, p73 G4C14-to-A4T14 polymorphism but not the p53 intron3 16 bp duplication polymorphism is associated with EC and its clinical characteristics in northern Indian population.

Mutational analysis of the PTEN gene and its effects in esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is one of the most frequently diagnosed cancers in China, but the etiology and mode of carcinogenesis of this disease remain poorly understood. The phosphatase and tensin homolog deleted from chromosome 10 (PTEN) with putative tumor suppressing is frequently mutated in many cancers.

AIMS

The aim of this study was to investigate whether there exists a mutation in the PTEN gene of the ESCC cells, and the effects of the wild type and mutated PTEN genes on the proliferation and apoptosis of the ESCC cells.

METHODS

The wild type and mutated PTEN genes were cloned from human placenta and ESCC cells, respectively, and their effects on the proliferation and apoptosis of the ESCC cells were investigated. Also, the relationship between the PTEN gene status and sensitivity of the EC9706 cells to cisplatin was determined in the xenografts of nude mice.

RESULTS

There were mutations in the PTEN gene from ESCC cells. The proliferation of the EC9706 cells was clearly inhibited by the wild type PTEN gene, but not by the mutated PTEN gene in vitro. Furthermore, the wild type PTEN gene inhibited the growth of transplantable tumor, induced cell apoptosis, and improved the sensitivity of the EC9706 cells to cisplatin in vivo.

CONCLUSION

The findings of the present study demonstrate that there are mutations in the PTEN gene of the ESCC cells and that the wild type PTEN gene has important effects on the ESCC cells in vitro and in vivo.

Occurrence of multipolar mitoses and association with Aurora-A/-B kinases and p53 mutations in aneuploid esophageal carcinoma cells

Background

Aurora kinases and loss of p53 function are implicated in the carcinogenesis of aneuploid esophageal cancers. Their association with occurrence of multipolar mitoses in the two main histotypes of aneuploid esophageal squamous cell carcinoma (ESCC) and Barrett's adenocarcinoma (BAC) remains unclear. Here, we investigated the occurrence of multipolar mitoses, Aurora-A/-B gene copy numbers and expression/activation as well as p53 alterations in aneuploid ESCC and BAC cancer cell lines.

Results

A control esophageal epithelial cell line (EPC-hTERT) had normal Aurora-A and -B gene copy numbers and expression, was p53 wild type and displayed bipolar mitoses. In contrast, both ESCC (OE21, Kyse-410) and BAC (OE33, OE19) cell lines were aneuploid and displayed elevated gene copy numbers of Aurora-A (chromosome 20 polysomy: OE21, OE33, OE19; gene amplification: Kyse-410) and Aurora-B (chromosome 17 polysomy: OE21, Kyse-410). Aurora-B gene copy numbers were not elevated in OE19 and OE33 cells despite chromosome 17 polysomy. Aurora-A expression and activity (Aurora-A/phosphoT288) was not directly linked to gene copy numbers and was highest in Kyse-410 and OE33 cells. Aurora-B expression and activity (Aurora-B/phosphoT232) was higher in OE21 and Kyse-410 than in OE33 and OE19 cells. The mitotic index was highest in OE21, followed by OE33 > OE19 > Kyse-410 and EPC-hTERT cells. Multipolar mitoses occurred with high frequency in OE33 (13.8 ± 4.2%), followed by OE21 (7.7 ± 5.0%) and Kyse-410 (6.3 ± 2.0%) cells. Single multipolar mitoses occurred in OE19 (1.0 ± 1.0%) cells. Distinct p53 mutations and p53 protein expression patterns were found in all esophageal cancer cell lines, but complete functional p53 inactivation occurred in OE21 and OE33 only.

Conclusions

High Aurora-A expression alone is not associated with overt multipolar mitoses in aneuploid ESCC and BAC cancer cells, as specifically shown here for OE21 and OE33 cells, respectively. Additional p53 loss of function mutations are necessary for this to occur, at least for invasive esophageal cancer cells. Further assessment of Aurora kinases and p53 interactions in cells or tissue specimens derived from non-invasive dysplasia (ESCC) or intestinal metaplasia (BAC) are necessary to disclose a potential causative role of Aurora kinases and p53 for development of aneuploid, invasive esophageal cancers.

Molecular imaging for guiding oncologic prognosis and therapy in esophageal adenocarcinoma

In the past 30 years, the incidence of esophageal adenocarcinoma (ACA) has increased significantly. Sadly, advances in treatment have not followed the same trend, and the prognosis for patients with esophageal ACA remains poor, with a 5-year survival rate of only 15%. Like most cancers, early detection is the key to improving prognosis, but this outcome has proven difficult in the esophagus for several reasons: 1) patients present with advanced disease because "alarm symptoms," such as dysphagia, occur at a late stage, and 2) high-grade dysplasia (HGD) and early ACA are not visible on routine surveillance endoscopy. Currently, the recommended surveillance strategy involves collection of random biopsies, an imperfect technique that is limited by sampling error and is infrequently used because of the considerable time and cost it requires. Even in patients with biopsy-proven dysplasia, adequate guidance for clinical management decisions is still lacking. Dysplasia alone is not an entirely reliable biomarker for the risk of progression to ACA because the natural history of this condition is extremely variable. Clearly, there is a need for additional biomarkers that can better characterize this disease and thus improve our ability to treat patients on an individual basis. As we better understand the molecular changes that lead to the development of this cancer, new molecular biomarkers are needed to allow for more personalized diagnoses, surveillance, and treatment. Targeted agents against epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and vascular endothelial growth factor (VEGF) are currently being evaluated for their role in combination chemotherapy for metastatic esophageal ACA. As these studies progress, a reliable approach for determining receptor status in individual patients is essential. Molecular imaging uses fluorescent probes that target specific cell-surface receptors, and has the potential to evaluate an individual patient's gene expression profile. By topically applying fluorescent probes to dysplastic epithelium during endoscopy, a variety of receptors can be visualized, and the response to treatment can be monitored in real time. This technique can mitigate the limitations of current surveillance protocols, allow for improved cancer detection, and be used for personalized treatment in the future.

Ki-67 and ProExC are useful immunohistochemical markers in esophageal squamous intraepithelial neoplasia

Esophageal squamous intraepithelial neoplasia has been widely recognized as a precursor lesion for esophageal squamous cell carcinoma. Early detection offers the best prognosis for esophageal squamous cell carcinoma. The differentiation of squamous dysplasia from reactive change and the classification of squamous dysplasia into high-grade or low-grade are sometimes subjective and challenging. In this study, we sought to evaluate multiple biomarkers and to develop clinically useful adjunct tools for difficult esophageal squamous intraepithelial neoplasia cases. Immunohistochemical stains using antibodies against Ki-67, ProExC, p16, and p53 were performed on esophageal biopsy or resection specimens from 25 patients including 35 foci of high-grade dysplasia and 25 foci of low-grade dysplasia, and from 10 control cases containing 52 foci of normal/reactive hyperplasia. In situ hybridization tests for human papillomavirus were performed in 11 cases. The immunostains for all 4 markers were scored as negative, intermediate, and strong according to established criteria. Intermediate and strong Ki-67 and ProExC staining showed similar detecting power and exhibited very high sensitivity and specificity for distinguishing normal/reactive hyperplasia from esophageal squamous intraepithelial neoplasia and normal/reactive hyperplasia from low-grade esophageal squamous intraepithelial neoplasia. Strong Ki-67 staining was exclusively seen in high-grade esophageal squamous intraepithelial neoplasia, which provided additional value in distinguishing high-grade from low-grade esophageal squamous intraepithelial neoplasia. Strong ProExC staining was also seen in most high-grade esophageal squamous intraepithelial neoplasia foci (80%). Although the frequencies of intermediate/strong staining patterns of p53 increased with increasing degree of dysplasia, the sensitivity of p53 was much lower than that of Ki-67 and ProExC. p16 did not show consistent immunostain pattern in the normal/reactive hyperplasia and esophageal squamous intraepithelial neoplasia. Two (18%) of 11 tested cases were positive for human papillomavirus infection. This study demonstrates that both Ki-67 and ProExC can be used as an adjunct tool for diagnosing difficult cases of esophageal squamous intraepithelial neoplasia.

Overexpression of GPR39 contributes to malignant development of human esophageal squamous cell carcinoma

Background

By using cDNA microarray analysis, we identified a G protein-coupled receptor, GPR39, that is significantly up-regulated in ESCC. The aim of this study is to investigate the role of GPR39 in human esophageal cancer development, and to examine the prevalence and clinical significance of GPR39 overexpression in ESCC.

Methods

The mRNA expression level of GPR39 was analyzed in 9 ESCC cell lines and 50 primary ESCC tumors using semi-quantitative RT-PCR. Immunohistochemistry was used to assess GPR39 protein expression in tissue arrays containing 300 primary ESCC cases. In vitro and in vivo studies were done to elucidate the tumorigenic role of GPR39 in ESCC cells.

Results

We found that GPR39 was frequently overexpressed in primary ESCCs in both mRNA level (27/50, 54%) and protein level (121/207, 58.5%), which was significantly associated with the lymph node metastasis and advanced TNM stage (P < 0.01). Functional studies showed that GPR39 has a strong tumorigenic ability. Introduction of GPR39 gene into ESCC cell line KYSE30 could promote cell proliferation, increase foci formation, colony formation in soft agar, and tumor formation in nude mice. The mechanism by which amplified GPR39 induces tumorigenesis was associated with its role in promoting G1/S transition via up-regulation of cyclin D1 and CDK6. Further study found GPR39 could enhance cell motility and invasiveness by inducing EMT and remodeling cytoskeleton. Moreover, depletion of endogenous GPR39 by siRNA could effectively decrease the oncogenicity of ESCC cells.

Conclusions

The present study suggests that GPR39 plays an important tumorigenic role in the development and progression of ESCC.

Prognostic significance of differentially expressed miRNAs in esophageal cancer

Altered microRNA (miRNA) expression has been found to promote carcinogenesis, but little is known about the role of miRNAs in esophageal cancer. In this study, we selected 10 miRNAs and analyzed their expression in 10 esophageal cancer cell lines and 158 tissue specimens using Northern blotting and in situ hybridization, respectively. We found that Let-7g, miR-21 and miR-195p were expressed in all 10 cell lines, miR-9 and miR-20a were not expressed in any of the cell lines, and miR-16-2, miR-30e, miR-34a, miR-126 and miR-200a were expressed in some of the cell lines but not others. In addition, transient transfection of miR-34a inhibited c-Met and cyclin D1 expression and esophageal cancer cell proliferation, whereas miR-16-2 suppressed RAR-β(2) expression and increased tumor cell proliferation. Furthermore, we found that miR-126 expression was associated with tumor cell dedifferentiation and lymph node metastasis, miR-16-2 was associated with lymph node metastasis, and miR-195p was associated with higher pathologic disease stages in patients with esophageal adenocarcinoma. Kaplan-Meier analysis showed that miR-16-2 expression and miR-30e expression were associated with shorter overall and disease-free survival in all esophageal cancer patients. In addition, miR-16-2, miR-30e and miR-200a expression were associated with shorter overall and disease-free survival in patients with esophageal adenocarcinoma; however, miR-16-2, miR-30e and miR-200a expression were not associated with overall or disease-free survival in squamous cell carcinoma patients. Our data indicate that further evaluation of miR-30e and miR-16-2 as prognostic biomarkers is warranted in patients with esophageal adenocarcinoma. In addition, the role of miR-34a in esophageal cancer also warrants further study.

Prognostic significance of p53 protein expression in early gastric cancer

Mutations of the p53 tumor suppressor gene have been associated with abnormalities in cell cycle regulation, DNA repair and synthesis, apoptosis, and it has been implicated in the prognosis of advanced gastric cancer. The aim of this study was to evaluate the occurrence of p53 gene mutation and its possible prognostic implications in early gastric cancer. In a retrospective study, we studied 80 patients with early gastric cancer treated surgically between 1982 and 2001. Mutation of p53 gene was investigated in surgical gastric specimens by immunohistochemistry, and results were analyzed in relation to gender, age, macroscopic appearance, size and location of tumor, presence of lymph nodes, Lauren's histological type, degree of differentiation, and the 5-year survival. The expression of p53 was more frequent among the intestinal type (p = 0.003), the differentiated (p = 0.007), and the macroscopically elevated tumors (p = 0.038). Nevertheless, the isolated expression of p53 was not associated with the 5-year survival, or with the frequency of lymph node involvement. The degree of differentiation was detected as an independent factor related to the outcome of patients (0.044). Significantly shorter survival time was found in p53-negative compared with p53-positive patients, when considering the degree of differentiation of tumors, as assessed by Cox regression analysis (0.049). The association of p53 with the intestinal type, the degree of differentiation and morphological characteristics, may reflect the involvement of chronic inflammatory process underlying early gastric cancer. In this population sample, the expression of p53 alone has no prognostic value for early gastric cancer. However, the significant difference in p53 expression between subgroups of degree of differentiation of tumors can influence post-operative outcome of patients and may be related to possible distinct etiopathogenic subtypes.

Association of p53/p21 expression with cigarette smoking and prognosis in esophageal squamous cell carcinoma patients

AIM: To investigate the expression of p53 and p21 and associations with possible risk factors, such as cigarette smoking, in esophageal squamous cell carcinoma (ESCC) in northeastern Iran, a region with a high incidence of ESCC.

METHODS: The expression of p53 and p21 proteins was investigated immunohistochemically in tumor tissue from 80 ESCC patients and in 60 available paraffin-embedded blocks of adjacent normal specimens from the cases, along with normal esophageal tissue from 80 healthy subjects.

RESULTS: Positive expression of p53 protein was detected in 56.2% (45/80) of ESCC cases, and in none of the normal esophageal tissue of the control group (P < 0.001). Furthermore, 73.8% (59/80) of ESCC cases and 43.8% (35/80) of controls had positive expression of p21 protein (P < 0.001). Cigarette smoking was significantly associated with p53 over-expression in ESCC cases (P = 0.010, OR = 3.64; 95% CI: 1.32-10.02). p21 over-expression was associated with poorer clinical outcome among the ESCC patients (P = 0.009).

CONCLUSION: Over-expression of p53 in association with cigarette smoking may play a critical role in ESCC carcinogenesis among this high-risk population of northeastern Iran. Furthermore, p21 over-expression was found to be associated with poor prognosis, specifically in the operable ESCC patients.

Molecular response prediction in multimodality treatment for adenocarcinoma of the esophagus and esophagogastric junction

Cancers arising from the esophagus are becoming more common in the United States and Europe. In 2009, an estimate of 14,530 new cases will be diagnosed and more than 90% will die of their disease. Esophageal cancer is currently the most rapidly increasing cancer in the western world and is coinciding with a shift in histological type and primary tumor location. Despite recent improvements in the detection, surgical resection, and (radio-) chemotherapy, the overall survival (OS) of esophageal cancer remains relatively poor. It is becoming increasingly apparent that neoadjuvant chemoradiation followed by surgery may be beneficial in terms of increasing resectability and OS compared to surgery alone. Results from clinical trials are encouraging; however, they also demonstrated that only patients with major histopathological response (pCR) will benefit from neoadjuvant therapy. In addition, these therapies are expensive and the prognoses of patients who do not respond to trimodality treatment strategies appear to be inferior to that of patients who had surgery alone. Accordingly, the development of validated predictive molecular markers may not only be helpful in identifying EA patients who are more likely to respond, but they will also be critical in selecting more efficient treatment strategies with the means of a tailored, targeted, and effective therapy to the molecular profile of both the patient and their disease while minimizing and avoiding life-threatening toxicities.

Clinical significance of GPR56, transglutaminase 2, and NF-κB in esophageal squamous cell carcinoma

Proteins do not operate as individual units, and components of intracellular canonical pathways often cross talk in tumor genesis. We hypothesized that G-protein-coupled receptor 56 (GPR56), transglutaminase (TG2), and nuclear factor-κB (NF-κB) may collaborate in interconnected pathways and contribute to the aggressive behavior of esophageal squamous cell carcinoma (ESCC). Immunohistochemical analysis of GPR56, TG2, and NF-κB was carried out using ESCC tissue microarrays. Immunostaining of all the three proteins revealed a significant increase in their expression in ESCCs as compared with normal epithelia and correlated with their concomitant expression. A significant correlation between GPR56, TG2, and NF-κB was observed that correlated with nodal metastasis and tumor invasion in ESCCs.

Study of abnormal chromosome regions in esophageal squamous cell carcinoma by comparative genomic hybridization: relationship of lymph node metastasis and distant metastasis to selected abnormal regions

Squamous cell carcinoma of the esophagus (ESCC) has a poor prognosis among digestive tract cancers. Lymph node metastasis and distant metastasis are the major factors determining its prognosis. We used comparative genomic hybridization (CGH) to evaluate primary tumor lymph nodes and metastatic areas from ESCC patients in order to determine the relationship between abnormal chromosome regions and outcome. Tumor tissues and lymph nodes were collected from 51 patients with ESCC, and abnormal chromosome regions were detected by CGH. We searched for regions that were significantly more common in patients with lymph nodes metastases (n>/= 6) or distant metastases, and correlated those chromosomal changes with survival. Regions showing amplification in more than 65% of esophageal squamous cell cancers were as follows: 17q12 (90.2%), 17q21 (86.3%), 3q29 (82.4%), 3q28 (78.4%), 8q24.2 (76.5%), 22q12 (76.5%), 3q27 (74.5%), 8q24.3 (74.5%), 1q22 (70.6%), 5p15.3 (70.6%), 22q13 (70.6%), 3q26.3, 8q23, 8q24.1, 9q34, 11q13, 17p12, 17q25, 20q12, 20q13.1 (68.6%), 1q32, 1q42, and 20q13.2 (66.7%). Regions showing deletion in more than 50% of the tumors were as follows: Yp11.3 (62.7%), 3p26 (56.9%), Yq12 (54.9%), 13q21 (52.9%), 4q32 (51.0%), and 13q22 (51.0%). When Fisher's test was used to assess associations of these regions with metastases to lymph nodes, amplification at 2q12-14 (P= 0.012), 3q24-26 (P= 0.005), and 7q21-31 (P= 0.026) were significant. Survival was worse for patients with amplification at all 3 regions. In patients with distant organ metastases, amplification at 7p13-21 was significant (P= 0.008), and survival was worse. Chromosomal amplifications in ESCC at 2q12-14, 3q24-26, and 7q21-31 were associated with lymph node metastasis, while amplification at 7p13-21 was related to distant metastasis. Amplification at these regions correlated with worse survival. Genes involved in the phenotype of ESCC may exist in these regions. Identification of these genes is a theme for future investigation.