CpG island hypermethylation in progression of esophageal and gastric cancer

Prognostic value of pre-operative mean corpuscular volume (MCV) in colorectal cancer

BACKGROUND

Mean corpuscular volume (MCV) has been shown to have some correlation to oncological outcomes in oesophageal cancer, with high pre-operative MCV associated with disease recurrence. A similar association has previously been reported in colorectal cancer.

AIMS

This study is aimed at investigating whether high MCV bears similar relation to post-operative outcome and disease recurrence in colorectal cancer (CRC).

METHODS

Patients undergoing elective CRC resection with curative intent between January 2008 and December 2019 were identified from our prospective database. Review of patient demographic details, American Society of Anaesthesiologists (ASA) grade, smoking and alcohol intake were performed. In addition, tumour location and staging, operation performed, pre-operative laboratory data and oncological management of each patient were noted. Post-operative morbidity (Clavien-Dindo (CD) score > 2), 30-day mortality, in-hospital mortality and cancer recurrence were examined and multivariable regression analysis was performed to predict these outcomes.

RESULTS

A total of 1,293 CRCs were resected, with 1,159 patients (89.7%) experiencing a hospital course without major morbidity (CD < 3). 30-day mortality rate was less than 1% (12/1293). There were 176 patients (13.6%) with recurrence at follow-up. When multivariable regression analysis was performed, high pre-operative MCV did not predict negative post-operative or oncological outcomes.

CONCLUSION

MCV does not appear to be an independent prognostic factor for outcomes following elective CRC resection.

Prognostic significance of mean corpuscular volume in patients with pancreatic ductal adenocarcinoma and multimodal treatment

AIM OF THE STUDY

Mean corpuscular volume (MCV) has shown mounting evidence as a prognostic indicator in a number of malignancies. The aim of this study was to examine the prognostic potential of pretherapeutic MCV among patients with pancreatic ductal adenocarcinoma (PDAC) who underwent upfront resection or resection after neoadjuvant treatment (NT).

PATIENTS AND METHODS

Consecutive patients with PDAC who underwent pancreatic resection between 1997 and 2019 were included in this study. Neoadjuvantly treated patients' serum MCV was measured before NT and before surgery. In patients undergoing upfront resection serum MCV was measured before surgery. Median MCV values were used as cut-off to distinguish high from low MCV values.

RESULTS

Five hundred and forty-nine (438 upfront resected and 111 neoadjuvantly treated) patients were included in this study. Multivariate analysis revealed, that high MCV before and after NT, were independent negative prognostic factors for overall survival (P<0.01, respectively). Furthermore, the median MCV value from before to after NT increased significantly (P<0.001, Wilcoxon signed-rank test) and was (P=0.03, Wilcoxon rank sum test) associated with tumor response to NT.

CONCLUSION

High MCV is an independent adverse prognostic factor in patients with resectable neoadjuvantly treated PDAC and may qualify as useful indicator to help physicians to provide personalized prognostication.

Role of the Microbiome in the Diagnosis and Management of Gastroesophageal Cancers

PURPOSE

Stomach and esophageal cancers are among the highest mortality from cancers worldwide. Microbiota has an interplaying role within the human gastrointestinal (GI) tract. Dysbiosis occurs when a disruption of the balance between the microbiota and the host happens. With this narrative review, we discuss the main alterations in the microbiome of gastroesophageal cancer, revealing its potential role in the pathogenesis, early detection, and treatment.

RESULTS

Helicobacter pylori plays a major role the development of a cascade of preneoplastic conditions ranging from atrophic gastritis to metaplasia and dysplasia, ultimately culminating in gastric cancer, while other pathogenic agents are Fusobacterium nucleatum, Bacteroides fragilis, Escherichia coli, and Lactobacillus. Campylobacter species (spp.)'s role in the progression of esophageal adenocarcinoma may parallel that of Helicobacter pylori in the context of gastric cancer, with other esophageal carcinogenic agents being Escherichia coli, Bacteroides fragilis, and Fusobacterium nucleatum. Moreover, gut microbiome could significantly alter the outcomes of chemotherapy and immunotherapy. The gut microbiome can be modulated through interventions such as antibiotics, probiotics, or prebiotics intake. Fecal microbiota transplantation has emerged as a therapeutic strategy as well.

CONCLUSIONS

Nowadays, it is widely accepted that changes in the normal gut microbiome causing dysbiosis and immune dysregulation play a role gastroesophageal cancer. Different interventions, including probiotics and prebiotics intake are being developed to improve therapeutic outcomes and mitigate toxicities associated with anticancer treatment. Further studies are required in order to introduce the microbiome among the available tools of precision medicine in the field of anticancer treatment.

Gut Microbiota in Colorectal Cancer: Biological Role and Therapeutic Opportunities

Colorectal cancer (CRC) is the second-leading cause of cancer-related deaths worldwide. While CRC is thought to be an interplay between genetic and environmental factors, several lines of evidence suggest the involvement of gut microbiota in promoting inflammation and tumor progression. Gut microbiota refer to the ~40 trillion microorganisms that inhabit the human gut. Advances in next-generation sequencing technologies and metagenomics have provided new insights into the gut microbial ecology and have helped in linking gut microbiota to CRC. Many studies carried out in humans and animal models have emphasized the role of certain gut bacteria, such as Fusobacterium nucleatum, enterotoxigenic Bacteroides fragilis, and colibactin-producing Escherichia coli, in the onset and progression of CRC. Metagenomic studies have opened up new avenues for the application of gut microbiota in the diagnosis, prevention, and treatment of CRC. This review article summarizes the role of gut microbiota in CRC development and its use as a biomarker to predict the disease and its potential therapeutic applications.

Interaction of Gut Microbiota with Endocrine Homeostasis and Thyroid Cancer

The gut microbiota plays a crucial role in healthy individuals as well as in patients with thyroid diseases, including thyroid cancer. Although the prognosis of differentiated thyroid cancer is predictable, that of some poorly differentiated, medullary, and anaplastic thyroid cancers remains unpromising. As the interaction between the gut microbiota and thyroid cancer has been gradually revealed in recent years, the thyroid gland, a crucial endocrine organ, is shown to have a complex connection with the body's metabolism and is involved in inflammation, autoimmunity, or cancer progression. Dysbiosis of the gut microbiota and its metabolites can influence changes in hormone levels and susceptibility to thyroid cancer through multiple pathways. In this review, we focus on the interactions of the gut microbiota with thyroid function diseases and thyroid cancer. In addition, we also discuss some potential new strategies for the prevention and treatment of thyroid disease and thyroid cancer. Our aim is to provide some possible clinical applications of gut microbiota markers for early diagnosis, treatment, and postoperative management of thyroid cancer. These findings were used to establish a better multi-disciplinary treatment and prevention management strategy and to individualize the treatment of patients in relation to their gut microbiota composition and pathological characteristics.

Interplay and cooperation of Helicobacter pylori and gut microbiota in gastric carcinogenesis

Chronic Helicobacter pylori infection is a critical risk factor for gastric cancer (GC). However, only 1–3 % of people with H. pylori develop GC. In gastric carcinogenesis, non-H. pylori bacteria in the stomach might interact with H. pylori. Bacterial dysbiosis in the stomach can strengthen gastric neoplasia development via generating tumor-promoting metabolites, DNA damaging, suppressing antitumor immunity, and activating oncogenic signaling pathways. Other bacterial species may generate short-chain fatty acids like butyrate that may inhibit carcinogenesis and inflammation in the human stomach. The present article aimed at providing a comprehensive overview of the effects of gut microbiota and H. pylori on the development of GC. Next, the potential mechanisms of intestinal microbiota were discussed in gastric carcinogenesis. We also disserted the complicated interactions between H. pylori, intestinal microbiota, and host in gastric carcinogenesis, thus helping us to design new strategies for preventing, diagnosing, and treating GC.

GSTs polymorphisms are associated with epigenetic silencing of CDKN2A gene in esophageal squamous cell carcinoma

Esophageal cancer is the eighth most common cancer and the sixth most frequent cause of cancer mortality worldwide. Exposure to polycyclic aromatic hydrocarbons formed by incomplete combustion of organic matter is an important risk factor. Genetic polymorphisms in genes encoding PAH-metabolizing enzymes like glutathione S-transferases (GSTM1, GSTP1, GSTT1) which conjugate glutathione to PAHs for reduction of oxidative stress may affect an individual's response to PAH exposure. Genomic DNA from 50 esophageal squamous cell carcinoma patients extracted from peripheral blood. PCR-RFLP technique was employed to determine GSTM1, GSTT1, and GSTP1 polymorphisms. Aberrant promoter methylation of CDKN2A was applied by methylation-specific PCR technique. Concentration of urinary 1-hydroxypyrene was determined using a HPLC system. About 38.7% showed the null GSTM1 genotype (54% cases and 13% controls), 23.7% showed GSTT1 null genotype (30% cases and 13% controls), and 62.5% were GSTP1 A/A genotype (66% cases and 56% controls). Polymorphic variants of GSTM1 and GSTT1 were significantly associated with aberrant methylation of CDKN2A gene. The null state of GSTT1 was significantly associated with high concentrations of 1-OHP in urea (p < 0.01). There was significant association between methylated states of CDKN2A and high concentrations of 1-OHP in urine (p < 0.01). We identified significant association between polymorphism of GSTs genes and epigenetic silencing of tumor suppressor gene CDKN2A in esophageal squamous cell carcinoma.

High Mean Corpuscular Volume as a Predictor of Poor Overall Survival in Patients with Esophageal Cancer Receiving Concurrent Chemoradiotherapy

Background

Increasing numbers of recent studies have demonstrated that high mean corpuscular volume (MCV) is a predictor of poor overall survival (OS) and therapeutic response in patients with solid tumors. The aim of the present study was to explore the association between high MCV and OS in patients with advanced esophageal cancer (EC) undergoing concurrent chemoradiotherapy.

Patients and Methods

Enrolled in this study were 249 patients with advanced EC who underwent concurrent chemoradiotherapy. Pre-treatment MCV values were collected in all patients and their correlations with OS and pathophysiological characteristics were analyzed. The chi-square test was used to explore the correlation between MCV and various clinical pathophysiological characteristics, and the prognostic significance of high MCV using Kaplan–Meier curves and the Cox proportional hazards model. All P-values were two-tailed and a P-value <0.05 was considered statistically significant.

Results

According to ROC curve analysis, the optimal cut-off value of MCV was 93.6 fL. The mean OS was 14.7 months in all 249 EC patients, 10.9 months in patients with MCV >93.6 fL, and 18.8 months in patients with MCV <93.6 fL; the difference is statistically significant (P<0.05). Chi-square test showed that the MCV value was correlated with the N stage of the tumor and the therapeutic effect, indicating that the higher the MCV was, the higher the T stage of the tumor and the worse the therapeutic effect would be (p=0.012 and p <0.01). Multivariate analysis showed that MCV (OR = 1.864, 95% CI: 1.439–2.415) was an independent prognostic factor for OS in EC patients.

Conclusion

High MCV is a poor predictor of OS in patients with advanced EC receiving concurrent chemoradiotherapy.

Update on gastric cancer treatments and gene therapies

Gastric cancer is an active topic of clinical and basic research due to high morbidity and mortality. To date, gastrectomy and chemotherapy are the only therapeutic options for gastric cancer patients, but drug resistance, either acquired or primary, is the main cause for treatment failure. Differences in development and response to cancer treatments have been observed among ethnically diverse GC patient populations. In spite of major incidence, GC Asian patients have a significantly better prognosis and response to treatments than Caucasian ones due to genetic discordances between the two populations. Gene therapy could be an alternative strategy to overcome such issues and especially CRISPR/Cas9 represents one of the most intriguing gene-editing system. Thus, in this review article, we want to provide an update on the currently used therapies for the treatment of advanced GC. Graphical abstract.

Genetic and molecular bases of esophageal Cancer among Iranians: an update

Abstract

Background

Esophageal cancer is one of the leading causes of cancer related deaths among the Iranians. There is still a high ratio of mortality and low 5 years survival which are related to the late onset and diagnosis. Majority of patients refer for the treatment in advanced stages of tumor progression.

Main body

It is required to define an efficient local panel of diagnostic and prognostic markers for the Iranians. Indeed such efficient specific panel of markers will pave the way to decrease the mortality rate and increase the 5 years survival among the Iranian patients via the early diagnosis and targeted therapy.

Conclusion

in present review we have reported all of the molecular markers in different signaling pathways and cellular processes which have been assessed among the Iranian esophageal cancer patients until now.

Genomic alterations in gastric cancers discovered via whole-exome sequencing

Background

Gastric cancer (GC) ranks the second in mortality rate among all cancers. Metastases account for most of the deaths in GC patients. Yet our understanding of GC and its metastasis mechanism is still very limited.

Methods

We performed 20 whole-exome sequencing (WES) on 5 typical metastatic gastric adenocarcinoma (GAC) patients with lymph node metastasis. We compared both the primary tumors to their metastatic lymph nodes, and a specific analysis pipeline was used to detect single nucleotide variants (SNVs), small insertions/deletions (indels) and copy number variants (CNVs).

Results

(1) We confirmed 30 candidate mutations in both primary and lymph nodes tissues, and other 7 only in primary tumors. (2) Copy number gains were observed in a large section of 17q12–21, as well as copy number losses in regions containing CDKN2A and CDKN2B in both primary and lymph nodes tissues.

Conclusions

Our results provide preliminary insights in the molecular mechanisms of GC initiation, development, and metastatic progression. These results need to be validated through large-scale studies.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5097-8) contains supplementary material, which is available to authorized users.

Helicobacter pylori pathogen regulates p14ARF tumor suppressor and autophagy in gastric epithelial cells

Infection with H. pylori pathogen is one of the strongest risk factors for development of gastric cancer. Although these bacteria infect approximately half of the world’s population, only a small fraction of infected individuals develops gastric malignancies. Interactions between host and bacterial virulence factors are complex and interrelated making it difficult to elucidate specific processes associated with H. pylori-induced tumorigenesis. In this study, we found that H. pylori inhibits p14ARF tumor suppressor by inducing its degradation. This effect was found to be strain-specific. Downregulation of p14ARF induced by H. pylori leads to inhibition of autophagy in a p53-independent manner in infected cells. We identified TRIP12 protein as E3 ubiquitin ligase that is upregulated by H. pylori, inducing ubiquitination and subsequent degradation of p14ARF protein. Using isogenic H. pylori mutants, we found that induction of TRIP12 is mediated by bacterial virulence factor CagA. Increased expression of TRIP12 protein was found in infected gastric epithelial cells in vitro and human gastric mucosa of H. pylori-infected individuals.

In conclusion, our data demonstrate a new mechanism of ARF inhibition that may affect host-bacteria interactions and facilitate tumorigenic transformation in the stomach.

Human Gut Microbiota and Gastrointestinal Cancer

Human gut microbiota play an essential role in both healthy and diseased states of humans. In the past decade, the interactions between microorganisms and tumors have attracted much attention in the efforts to understand various features of the complex microbial communities, as well as the possible mechanisms through which the microbiota are involved in cancer prevention, carcinogenesis, and anti-cancer therapy. A large number of studies have indicated that microbial dysbiosis contributes to cancer susceptibility via multiple pathways. Further studies have suggested that the microbiota and their associated metabolites are not only closely related to carcinogenesis by inducing inflammation and immune dysregulation, which lead to genetic instability, but also interfere with the pharmacodynamics of anticancer agents. In this article, we mainly reviewed the influence of gut microbiota on cancers in the gastrointestinal (GI) tract (including esophageal, gastric, colorectal, liver, and pancreatic cancers) and the regulation of microbiota by diet, prebiotics, probiotics, synbiotics, antibiotics, or the Traditional Chinese Medicine. We also proposed some new strategies in the prevention and treatment of GI cancers that could be explored in the future. We hope that this review could provide a comprehensive overview of the studies on the interactions between the gut microbiota and GI cancers, which are likely to yield translational opportunities to reduce cancer morbidity and mortality by improving prevention, diagnosis, and treatment.

Human Gut Microbiota and Gastrointestinal Cancer

Human gut microbiota play an essential role in both healthy and diseased states of humans. In the past decade, the interactions between microorganisms and tumors have attracted much attention in the efforts to understand various features of the complex microbial communities, as well as the possible mechanisms through which the microbiota are involved in cancer prevention, carcinogenesis, and anti-cancer therapy. A large number of studies have indicated that microbial dysbiosis contributes to cancer susceptibility via multiple pathways. Further studies have suggested that the microbiota and their associated metabolites are not only closely related to carcinogenesis by inducing inflammation and immune dysregulation, which lead to genetic instability, but also interfere with the pharmacodynamics of anticancer agents. In this article, we mainly reviewed the influence of gut microbiota on cancers in the gastrointestinal (GI) tract (including esophageal, gastric, colorectal, liver, and pancreatic cancers) and the regulation of microbiota by diet, prebiotics, probiotics, synbiotics, antibiotics, or the Traditional Chinese Medicine. We also proposed some new strategies in the prevention and treatment of GI cancers that could be explored in the future. We hope that this review could provide a comprehensive overview of the studies on the interactions between the gut microbiota and GI cancers, which are likely to yield translational opportunities to reduce cancer morbidity and mortality by improving prevention, diagnosis, and treatment.

Silencing DNA methyltransferase 1 leads to the activation of the esophageal suppressor gene p16 in vitro and in vivo

Previous studies have demonstrated that DNA methyltransferase 1 (DNMT1) is required for the maintenance of DNA methylation and epigenetic changes that may lead to the development of esophageal squamous cell carcinoma (ESCC). In order to investigate whether the silencing of DNMT1 protects tumor suppressor genes, including p16, and is able to be used as a potential therapy for human ESCC, short hairpin RNA targeting DNMT1 (shRNA-DNMT1) was synthesized and transfected into the human ESCC lines KYSE150 and KYSE410, which were then injected into the backs of nude mice prior to harvesting. Results from the reverse transcription-quantitative polymerase chain reaction (PCR) and western blotting demonstrated that p16 mRNA expression was increased in the shRNA-DNMT1-transfected ESCC cell lines in vitro and in vivo. Consistent with the immunohistochemistry results, p16 was expressed in tumor tissue from nude mice that had been transplanted with the modified human ESCC lines. It was also observed that p16 methylation was inhibited following transfection with shRNA-DNMT1 as detected using methylation-specific PCR analysis. The results of the present study suggest that silencing DNMT1 serves a protective role through the demethylation and subsequent activation of p16 in vitro and in vivo.

Aberrant GSTP1 promoter methylation predicts poor prognosis of acute-on-chronic hepatitis B pre-liver failure

It has been demonstrated that glutathione-S-transferase P1 (GSTP1) could protect cells from DNA damage mediated by oxidizing agents or electrophiles in hepatic inflammatory response. Our study evaluated the methylation status and the predictive value for prognosis of GSTP1 promoter region in patients with acute-on-chronic hepatitis B pre-liver failure (pre-ACHBLF). Methylation status of GSTP1 promoter in peripheral blood mononuclear cells (PBMCs) and plasma was measured in 103 patients with pre-ACHBLF, 80 patients with chronic hepatitis B (CHB) and 30 healthy controls (HCs) by methylation-specific polymerase chain reaction. The mRNA level of GSTP1 was detected by quantitative real-time polymerase chain reaction. The methylation frequency of GSTP1 promoter region in patients with pre-ACHBLF (35/103 in PBMCs and 33/103 in plasma) was significantly higher than CHB (2/80) and HCs (0/30), respectively. The mRNA level of GSTP1 in patients with pre-ACHBLF was significantly lower than CHB and HCs. Additionally, pre-ACHBLF patients with methylated GSTP1 presented strikingly higher incidence of ACHBLF than those without. Of note, GSTP1 methylation presented distinctly better performance than model for end-stage liver disease score [area under the receiver operating characteristic curves (AUCs) 0.825 in PBMCs and 0.798 in plasma VS 0.589; AUC 0.804 in PBMCs and 0.779 in plasma VS 0.622; AUC 0.767 in PBMCs and 0.744 in plasma VS 0.602, respectively] when used to predict the 1-, 2- or 3-month incidence of ACHBLF in patients with pre-ACHBLF. Aberrant methylation of GSTP1 has potential to be a prognostic biomarker for pre-ACHBLF.

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.

Morphological Features and Prognostic Significance of ARID1A-Deficient Esophageal Adenocarcinomas

Context.—

The clinicopathologic and prognostic significance of ARID1A mutation in esophageal adenocarcinoma (EAC) is unknown.

Objective.—

To determine the morphological correlates and prognostic significance of ARID1A-deficient EAC.

Design.—

One hundred twenty cases of primary EAC were evaluated for a predetermined set of histologic features and immunohistochemistry for ARID1A, p53, and MLH1 performed on EAC, as well as adjacent Barrett esophagus and Barrett esophagus–associated dysplasia, when feasible. Associations between categorical clinicopathologic variables were analyzed by Fisher exact test, and survival analysis was performed by a Cox proportional hazards analysis.

Results.—

The study group included 97 men and 23 women (mean age, 66 years). Loss of ARID1A expression was seen in 12 of 120 EACs (10%). ARID1A-deficient tumors showed a strong correlation with a medullary and mucinous phenotype, and 8 of 12 (67%) had at least one feature reminiscent of high microsatellite instability colon carcinomas (mucinous or medullary differentiation, marked intratumoral or peritumoral lymphoid infiltrate). A mutant p53 pattern was present in 52 of 120 EACs (43%) and showed no correlation with ARID1A deficiency (P &gt; .05). MLH1 loss was present in only 2 of 120 EACs (2%); both of which were also deficient in ARID1A. ARID1A-deficient EACs showed a trend toward increased risk of nodal metastasis but had no effect on overall patient survival.

Conclusions.—

ARID1A-deficient EACs show a phenotype similar to colon cancer with high microsatellite instability but do not appear to have any prognostic significance. Concurrent MLH1 loss is not seen in most ARID1A-deficient tumors, suggesting that ARID1A may be a primary driver of carcinogenesis in a subset of EACs.

Influence of MTHFR Genetic Background on p16 and MGMT Methylation in Oral Squamous Cell Cancer

Genetic polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) enzyme may influence DNA methylation. Alterations in DNA methylation patterns of genes involved in the regulation of the cell cycle, DNA repair, cell adherence and metastasis process are known to contribute to cancer development. In this study, the influence of the MTHFR C677T and A1298C gene polymorphisms on global DNA methylation and site-specific methylation on p16 and O⁶-methylguanine-DNA methyltransferase (MGMT) gene promoters was investigated in patients with oral squamous cell cancer (OSCC). To this aim, methylation studies were carried out by using genomic DNA isolated from saliva samples of 58 OSCC patients and 90 healthy controls. The frequency of the CT/AC and TT/AA genotypes was significantly higher in patients than in controls. Whereas no difference in global DNA methylation levels was observed between patients and controls, a higher frequency of methylation at both p16 and MGMT gene promoters was detected in patients compared with controls. A significant association between MTHFR gene polymorphisms and p16 and MGMT gene promoter methylation was found. The frequency of p16 and MGMT methylation was around 60% in patients with either the CT/AC or TT/AA genotype. Our results suggest that hypermethylation of cancer-related genes may be affected by MTHFR polymorphisms.

CpG island methylator phenotype in adenocarcinomas from the digestive tract: Methods, conclusions, and controversies

Over the last two decades, cancer-related alterations in DNA methylation that regulate transcription have been reported for a variety of tumors of the gastrointestinal tract. Due to its relevance for translational research, great emphasis has been placed on the analysis and molecular characterization of the CpG island methylator phenotype (CIMP), defined as widespread hypermethylation of CpG islands in clinically distinct subsets of cancer patients. Here, we present an overview of previous work in this field and also explore some open questions using cross-platform data for esophageal, gastric, and colorectal adenocarcinomas from The Cancer Genome Atlas. We provide a data-driven, pan-gastrointestinal stratification of individual samples based on CIMP status and we investigate correlations with oncogenic alterations, including somatic mutations and epigenetic silencing of tumor suppressor genes. Besides known events in CIMP such as BRAF V600E mutation, CDKN2A silencing or MLH1 inactivation, we discuss the potential role of emerging actors such as Wnt pathway deregulation through truncating mutations in RNF43 and epigenetic silencing of WIF1. Our results highlight the existence of molecular similarities that are superimposed over a larger backbone of tissue-specific features and can be exploited to reduce heterogeneity of response in clinical trials.

Gastric Cancer in the Era of Precision Medicine

Gastric cancer (GC) remains the third most common cause of cancer death worldwide, with limited therapeutic strategies available. With the advent of next-generation sequencing and new preclinical model technologies, our understanding of its pathogenesis and molecular alterations continues to be revolutionized. Recently, the genomic landscape of GC has been delineated. Molecular characterization and novel therapeutic targets of each molecular subtype have been identified. At the same time, patient-derived tumor xenografts and organoids now comprise effective tools for genetic evolution studies, biomarker identification, drug screening, and preclinical evaluation of personalized medicine strategies for GC patients. These advances are making it feasible to integrate clinical, genome-based and phenotype-based diagnostic and therapeutic methods and apply them to individual GC patients in the era of precision medicine.

Epigenetic roles in the malignant transformation of gastric mucosal cells

Gastric carcinogenesis occurs when gastric epithelial cells transition through the initial, immortal, premalignant, and malignant stages of transformation. Epigenetic regulations contribute to this multistep process. Due to the critical role of epigenetic modifications , these changes are highly likely to be of clinical use in the future as new biomarkers and therapeutic targets for the early detection and treatment of cancers. Here, we summarize the recent findings on how epigenetic modifications, including DNA methylation, histone modifications, and non-coding RNAs, regulate gastric carcinogenesis, and we discuss potential new strategies for the diagnosis and treatments of gastric cancer. The strategies may be helpful in the further understanding of epigenetic regulation in human diseases.

Phase I Study of Epigenetic Priming with Azacitidine Prior to Standard Neoadjuvant Chemotherapy for Patients with Resectable Gastric and Esophageal Adenocarcinoma: Evidence of Tumor Hypomethylation as an Indicator of Major Histopathologic Response

Purpose: Epigenetic silencing of tumor suppressor genes (TSG) is an acquired abnormality observed in cancer and is prototypically linked to DNA methylation. We postulated that pretreatment (priming) with 5-azacitidine would increase the efficacy of chemotherapy by reactivating TSGs. This study was conducted to identify a tolerable dose of 5-azacitidine prior to EOX (epirubicin, oxaliplatin, capecitabine) neoadjuvant chemotherapy in patients with locally advanced esophageal/gastric adenocarcinoma (EGC).Experimental Design: Eligible patients had untreated, locally advanced, resectable EGC, ECOG 0-2, and adequate organ function. 5-Azacitidine (V, 75 mg/m²) was given subcutaneously for 3 (dose level, DL 1) or 5 (DL 2) days prior to each 21-day cycle of EOX (E, 50 mg/m²; O, 130 mg/m²; X, 625 mg/m² twice daily for 21 days). Standard 3+3 methodology guided V dose escalation. DNA methylation at control and biomarker regions was measured by digital droplet, bisulfite qPCR in tumor samples collected at baseline and at resection.Results: All subjects underwent complete resection of residual tumor (R0). Three of the 12 patients (25%) achieved a surgical complete response and 5 had partial responses. The overall response rate was 67%. The most common toxicities were gastrointestinal and hematologic. Hypomethylation of biomarker genes was observed at all dose levels and trended with therapeutic response.Conclusions: Neoadjuvant VEOX was well-tolerated with significant clinical and epigenetic responses, with preliminary evidence that priming with V prior to chemotherapy may augment chemotherapy efficacy. The recommended phase II trial schedule is 5-azacitidine 75 mg/m² for 5 days followed by EOX chemotherapy every 21 days. Clin Cancer Res; 23(11); 2673-80. ©2016 AACR.

Silencing NKD2 by promoter region hypermethylation promotes gastric cancer invasion and metastasis by up-regulating SOX18 in human gastric cancer

Naked cuticle homolog2 (NKD2) is located in chromosome 5p15.3, which is frequently loss of heterozygosity in human colorectal and gastric cancers. In order to understand the mechanism of NKD2 in gastric cancer development, 6 gastric cancer cell lines and 196 cases of human primary gastric cancer samples were involved. Methylation specific PCR (MSP), gene expression array, flow cytometry, transwell assay and xenograft mice model were employed in this study. The expression of NKD1 and NKD2 was silenced by promoter region hypermethylation. NKD1 and NKD2 were methylated in 11.7% (23/196) and 53.1% (104/196) in human primary gastric cancer samples. NKD2 methylation is associated with cell differentiation, TNM stage and distant metastasis significantly (all P < 0.05), and the overall survival time is longer in NKD2 unmethylated group compared to NKD2 methylated group (P < 0.05). Restoration of NKD2 expression suppressed cell proliferation, colony formation, cell invasion and migration, induced G2/M phase arrest, and sensitized cancer cells to docetaxel. NKD2 inhibits SOX18 and MMP-2,7,9 expression and suppresses BGC823 cell xenograft growth. In conclusion, NKD2 methylation may serve as a poor prognostic and chemo-sensitive marker in human gastric cancer. NKD2 impedes gastric cancer metastasis by inhibiting SOX18.

Measurement of DNA Length Changes Upon CpG Hypermethylation by Microfluidic Molecular Stretching

Abnormal DNA methylation in CpG-rich promoters is recognized as a distinct molecular feature of precursor lesions to cancer. Such unintended methylation can occur during in vitro differentiation of stem cells. It takes place in a subset of genes during the differentiation or expansion of stem cell derivatives under general culture conditions, which may need to be monitored in future cell transplantation studies. Here we demonstrate a microfluidic device for investigating morphological length changes in DNA methylation. Arrayed polymer chains of single DNA molecules were fluorescently observed by parallel trapping and stretching in the microfluidic channel. This observational study revealed that the shortened DNA length is due to the increased rigidity of the methylated DNA molecule. The trapping rate of the device for DNA molecules was substantially unaffected by changes in the CpG methylation.

Post-ablation surveillance in Barrett's esophagus: A review of the literature

Barrett’s esophagus (BE) is a pre-malignant condition affecting up to 15% of patients with gastroesophageal reflux disease. Neoplastic Barrett’s mucosa is defined as harboring high grade dysplasia or intra-mucosal cancer, and carries a high risk of progression to esophageal adenocarcinoma. The rising incidence of Barrett’s lesions along with the high morbidity of surgical approaches has led to the development of numerous validated endoscopic techniques capable of eradicating neoplastic mucosa in a minimally invasive manner. While there has been widespread adoption of these techniques, less is known about optimal surveillance intervals in the post-therapy period. This is due in part to limitations in current surveillance methods, questions about durability of treatment response and the risk of subendothelial progression. As we are now able to achieve organ sparing eradication of superficial neoplasia in BE, we need to also then focus our attention on how best to manage these patients after eradication is achieved. Implementing optimal surveillance practices requires additional understanding of the biology of the disease, appreciation of the limits of current tools and treatments, and exploration of the role of adjunctive technologies. The aim of this article is to provide a comprehensive review of current literature surrounding post-ablation surveillance in neoplastic BE.

Genome-wide hypomethylation and specific tumor-related gene hypermethylation are associated with esophageal squamous cell carcinoma outcome

INTRODUCTION

Esophageal squamous cell carcinoma (ESCC) is a cancer of variable outcomes with limited effective treatments resulting in poor overall survival (OS). Epigenetic alterations contributing to this deadly cancer type that can be used as novel therapeutic or diagnostic targets are still poorly understood.

METHODS

We explored genome-wide DNA methylation data from The Cancer Genome Atlas project and identified a panel of tumor-related genes hypermethylated in ESCC. The methylation statuses of RASSF1, RARB, CDKN2A (p16INK4a, p14ARF), APC, and RUNX3 genes and long interspersed nucleotide element-1 (LINE-1) were validated in a large cohort (n = 140) of clinically well-annotated ESCC specimens and esophageal normal mucosa (n = 28) using a quantitative methylation-specific polymerase chain reaction.

RESULTS

Hypermethylation of RARB, p16INK4a, RASSF1, APC, RUNX3, and p14ARF were observed in 55%, 24%, 20%, 19%, 14%, and 8% of specimens, respectively. Hypermethylation of APC was significantly associated with tumor depth (p = 0.02) and American Joint Committee on Cancer stage (p = 0.03). Global DNA methylation level, assessed by LINE-1, was significantly lower in ESCC than in normal mucosa (p < 0.0001), and lower in greater than or equal to T2 (n = 69) than T1 tumors (n = 45; p = 0.03). There was a significant inverse correlation between LINE-1 and RARB methylation (p = 0.008). Importantly, hypermethylation of RASSF1 and APC genes was significantly associated with overall survival (OS; p = 0.006 and p = 0.007, respectively). In addition, patients with tumors containing a higher number of methylated genes (greater than two genes) presented worse OS (p = 0.003).

CONCLUSIONS

This study demonstrates that epigenetic alterations of a panel of tumor-related genes and the noncoding region LINE-1 can be used as prognostic indicators and help in clinical management of ESCC patients.

Expression of interleukin 1β in gastric cancer tissue and its effects on gastric cancer

This study detected the expression level of IL-1β in gastric cancer tissue and paracarcinoma tissue, and also analyzed its relationship with clinical and pathological features, so as to explore the expression of IL-1β in gastric cancer tissue and its effect on gastric cancer. A total of 70 fresh primary gastric cancer tumors and corresponding paracarcinoma tissues away from the tumor-incision edge (≥5 cm) were selected from the First Affiliated Hospital of Zhengzhou University from January to December 2014. Total protein concentration was extracted from tissues with radioimmunoprecipitation assay lysis buffer, and IL-1β content in tissues was detected with enzyme-linked immunosorbent assay. The ratio of cell cytokine content and protein concentration was considered as the relative content of cytokines, and the relationship between relative content of cytokines and clinical data was analyzed. Results indicated that the differences in content of IL-1β in gastric cancer tissues and paracarcinoma tissues had no statistical significance, but the content of IL-1β would rise as tumor size was enlarged, based upon analysis (2.9<4.2 ng/g), and the difference was statistically significant (P<0.05). Furthermore, IL-1β content decreased along with differentiation degree and infiltration depth (3.21<4.15 ng/g, 3.06<3.45 ng/g), but the difference was not statistically significant (P>0.05). Therefore, it can be concluded that IL-1β plays an important role in the occurrence and development of gastric cancer and promotes the treatment of gastric cancer to some extent.

Challenges of deciphering gastric cancer heterogeneity

Gastric cancer is in decline in most developed countries; however, it still accounts for a notable fraction of global mortality and morbidity related to cancer. High-throughput methods are rapidly changing our view and understanding of the molecular basis of gastric carcinogenesis. Today, it is widely accepted that the molecular complexity and heterogeneity, both inter- and intra-tumour, of gastric adenocarcinomas present significant obstacles in elucidating specific biomarkers for early detection of the disease. Although genome-wide sequencing and gene expression studies have revealed the intricate nature of the molecular changes that occur in tumour landscapes, the collected data and results are complex and sometimes contradictory. Several aberrant molecules have already been tested in clinical trials, although their diagnostic and prognostic utilities have not been confirmed thus far. The gold standard for the detection of sporadic gastric cancer is still the gastric endoscopy, which is considered invasive. In addition, genome-wide association studies have confirmed that genetic variations are important contributors to increased cancer risk and could participate in the initiation of malignant transformation. This hypothesis could in part explain the late onset of sporadic gastric cancers. The elaborate interplay of polymorphic low penetrance genes and lifestyle and environmental risk factors requires additional research to decipher their relative impacts on tumorigenesis. The purpose of this article is to present details of the molecular heterogeneity of sporadic gastric cancers at the DNA, RNA, and proteome levels and to discuss issues relevant to the translation of basic research data to clinically valuable tools. The focus of this work is the identification of relevant molecular changes that could be detected non-invasively.

Helicobacter pylori virulence factor CagA promotes tumorigenesis of gastric cancer via multiple signaling pathways

Helicobacter pylori (H. pylori) infection is strongly associated with the development of gastric diseases but also with several extragastric diseases. The clinical outcomes caused by H. pylori infection are considered to be associated with a complex combination of host susceptibility, environmental factors and bacterial isolates. Infections involving H. pylori strains that possess the virulence factor CagA have a worse clinical outcome than those involving CagA-negative strains. It is remarkable that CagA-positive H. pylori increase the risk for gastric cancer over the risk associated with H. pylori infection alone. CagA behaves as a bacterial oncoprotein playing a key role in H. pylori-induced gastric cancer. Activation of oncogenic signaling pathways and inactivation of tumor suppressor pathways are two crucial events in the development of gastric cancer. CagA shows the ability to affect the expression or function of vital protein in oncogenic or tumor suppressor signaling pathways via several molecular mechanisms, such as direct binding or interaction, phosphorylation of vital signaling proteins and methylation of tumor suppressor genes. As a result, CagA continuously dysregulates of these signaling pathways and promotes tumorigenesis. Recent research has enriched our understanding of how CagA effects on these signaling pathways. This review summarizes the results of the most relevant studies, discusses the complex molecular mechanism involved and attempts to delineate the entire signaling pathway.

Bacterial CagA protein induces degradation of p53 protein in a p14ARF-dependent manner

OBJECTIVE

Infection with Helicobacter pylori is the strongest known risk factor for adenocarcinoma of the stomach. Tumorigenic transformation of gastric epithelium induced by H. pylori is a highly complex process driven by an active interplay between bacterial virulence and host factors, many aspects of which remain obscure. In this work, we investigated the degradation of p53 tumour suppressor induced by H. pylori.

DESIGN

Expression of p53 protein in gastric biopsies was assessed by immunohistochemistry. Gastric cells were co-cultured with H. pylori strains isolated from high-gastric risk and low-gastric risk areas and assessed for expression of p53, p14ARF and cytotoxin-associated gene A (CagA) by immunoblotting. siRNA was used to inhibit activities of ARF-BP1 and Human Double Minute 2 (HDM2) proteins.

RESULTS

Our analysis demonstrated that H. pylori strains expressing high levels of CagA virulence factor and associated with a higher gastric cancer risk more strongly suppress p53 compared with low-risk strains in vivo and in vitro. We found that degradation of p53 induced by bacterial CagA protein is mediated by host HDM2 and ARF-BP1 E3 ubiquitin ligases, while the p14ARF protein counteracts H. pylori-induced signalling.

CONCLUSIONS

Our results provide novel evidence that tumorigenicity associated with H. pylori infection is linked to inhibition of p53 protein by CagA. We propose a model in which CagA-induced degradation of p53 protein is determined by a relative level of p14ARF. In cells in which p14ARF levels were decreased due to hypermethylation or deletion of the p14ARF gene, H. pylori efficiently degraded p53, whereas p53 is protected in cells expressing high levels of p14ARF.

Differential Expression of ADAM23, CDKN2A (P16), MMP14 and VIM Associated with Giant Cell Tumor of Bone

Though benign, giant cell tumor of bone (GCTB) can become aggressive and can exhibit a high mitotic rate, necrosis and rarely vascular invasion and metastasis. GCTB has unique histologic characteristics, a high rate of multinucleated cells, a variable and unpredictable growth potential and uncertain biological behavior. In this study, we sought to identify genes differentially expressed in GCTB, thus building a molecular profile of this tumor. We performed quantitative real-time polymerase chain reaction (qPCR), immunohistochemistry and analyses of methylation to identify genes that are putatively associated with GCTB. The expression of the ADAM23 and CDKN2A genes was decreased in GCTB samples compared to normal bone tissue, measured by qPCR. Additionally, a high hypermethylation frequency of the promoter regions of ADAM23 and CDKN2A in GCTB was observed. The expression of the MAP2K3, MMP14, TIMP2 and VIM genes was significantly higher in GCTB than in normal bone tissue, a fact that was confirmed by qPCR and immunohistochemistry. The set of genes identified here furthers our understanding of the molecular basis of GCTB.

Clinical Significance of MLH1 Methylation and CpG Island Methylator Phenotype as Prognostic Markers in Patients with Gastric Cancer

BACKGROUND

To improve the outcome of patients suffering from gastric cancer, a better understanding of underlying genetic and epigenetic events in this malignancy is required. Although CpG island methylator phenotype (CIMP) and microsatellite instability (MSI) have been shown to play pivotal roles in gastric cancer pathogenesis, the clinical significance of these events on survival outcomes in patients with gastric cancer remains unknown.

METHODS

This study included a patient cohort with pathologically confirmed gastric cancer who had surgical resections. A cohort of 68 gastric cancers was analyzed. CIMP and MSI statuses were determined by analyzing promoter CpG island methylation status of 28 genes/loci, and genomic instability at 10 microsatellite markers, respectively. A Cox's proportional hazards model was performed for multivariate analysis including age, stage, tumor differentiation, KRAS mutation status, and combined CIMP/MLH1 methylation status in relation to overall survival (OS).

RESULTS

By multivariate analysis, longer OS was significantly correlated with lower pathologic stage (P = 0.0088), better tumor differentiation (P = 0.0267) and CIMP-high and MLH1 3' methylated status (P = 0.0312). Stratification of CIMP status with regards to MLH1 methylation status further enabled prediction of gastric cancer prognosis.

CONCLUSIONS

CIMP and/or MLH1 methylation status may have a potential to be prognostic biomarkers for patients with gastric cancer.

Epigenetics of gastric cancer

Epigenetic changes frequently occur in human gastric cancer. Gene promoter region hypermethylation, genomic global hypomethylation, histone modifications, and alterations of noncoding RNAs are major epigenetic changes in gastric cancer. As a key risk factor of gastric cancer, H. pylori infection is an independent predictive indicator of gene methylation. A growing number of epigenetic studies in gastric cancer have provided lots of potential diagnostic and prognostic markers and therapeutic targets.

Lower mean corpuscular hemoglobin concentration is associated with unfavorable prognosis of resected lung cancer

ABSTRACT 

Background: The association of preoperative red blood cell indexes in non-anemic patients undergoing lung resections for non-small-cell lung cancer with recurrence-free survival (RFS) and overall survival (OS) has never been investigated. Methods: We retrospectively examined the impact of preoperative red blood cell indexes on RFS and OS and the relationships between the indexes and clinicopathological factors in lung cancer. Results: A total of 649 patients were evaluated. The mean corpuscular hemoglobin concentration was showed as an independent prognostic factor in all patients for OS (hazard ratio [HR]: 0.697; 95% CI: 0.502–0.969; p = 0.032) and RFS (HR: 0.688; 95% CI: 0.519–0.914; p = 0.010). The mean corpuscular volume was an independent prognostic factor in all patients for OS (HR: 0.589; 95% CI: 0.380–0.912; p = 0.018), but not for RFS (HR: 0.684; 95% CI: 0.461–1.015; p = 0.059). Conclusion: In conclusion, the results of this study suggest that mean corpuscular hemoglobin concentration is an independent prognostic factor for OS and RFS in non-small-cell lung cancer.

Aberrant DNA methylation of P16, MGMT, hMLH1 and hMSH2 genes in combination with the MTHFR C677T genetic polymorphism in gastric cancer

Associations of P16, MGMT, hMLH1 and hMLH2 with gastric cancer and their relation with MTHFR status in gastric patients who were confirmed with pathological diagnosis were assessed. Aberrant DNA methylation of P16, MGMT, hMLH1 and hMLH2 and polymorphisms of MTHFR C677T were assayed. The proportional DNA hypermethylation in P16, MGMT, hMLH1 and hMLH2 in cancer tissues was significantly higher than in remote normal-appearing tissues. DNA hypermethylation of P16 and MGMT was correlated with the T and N stages. Individuals with homozygotes (TT) of MTHFR C677T had significant risk of hypermethylation of MGMT in cancer tissues [OR (95% CI)= 3.47(1.41-7.93)]. However, we did not find association between polymorphism in MTHFR C677T and risk of hypermethylation in P16, MGMT, hMLH1 and hMLH2 genes either in cancer or remote normal-appearing tissues. Aberrant hypermethylation of P16, MGMT, hMLH1 and hMLH2 could be predictive of gastric cancer.

Clinical significance of the methylated cytosine-phosphate-guanine sites of protocadherin-10 promoter for evaluating the prognosis of gastric cancer

BACKGROUND

Protocadherin-10 (PCDH10) has been identified as a tumor suppressor gene in multiple carcinomas. In this study, we intended to elucidate the clinical applicability of the methylation of CpG sites of PCDH10 promoter for prognostic prediction in gastric cancer (GC).

STUDY DESIGN

Qualitative and quantitative detections of PCDH10 promoter methylation were performed with methylation-specific polymerase chain reaction (MSP) and bisulphite genomic sequencing, respectively. The methylated statuses of 27 cytosine-phosphate-guanine (CpG) sites in PCDH10 promoter were detected in a series of 458 GC tissues to supply precise information of prognostic prediction. Associations between molecular, clinicopathologic, and survival data were analyzed.

RESULTS

Protocadherin-10 promoter methylation was found in 91.92% in all patients. Gastric cancer patients with 5 or more methylated CpG sites of PCDH10 promoter was significantly associated with poorer survival (p = 0.038). Meanwhile, methylation of combined CpG (-115, -108, -13, and +3) sites was also identified to provide elaborate survival discrimination for GC patients (p = 0.044). On multivariate survival analysis, methylation of combined CpG (-115, -108, -13, and +3) sites (hazard ratio [HR] = 1.255; p = 0.049) was identified to be an independent prognostic indicator of GC, as were N stage and T stage. Additionally, the methylation of combined CpG (-115, -108, -13, and +3) sites had smaller Akaike information criterion (AIC) and Bayesian information criterion (BIC) values than the other 2 independent predictors of the survival. Ultimately, we demonstrated that the methylation of combined CpG (-115, -108, -13, and +3) sites was negatively associated with PCDH10 expression in GC tissues.

CONCLUSIONS

The methylated CpG sites of PCDH10 promoter had significant applicability for clinical evaluation of the prognosis of GC.

Silencing DACH1 promotes esophageal cancer growth by inhibiting TGF-β signaling

Human Dachshund homologue 1 (DACH1) is a major component of the Retinal Determination Gene Network. Loss of DACH1 expression was found in breast, prostate, lung, endometrial, colorectal and hepatocellular carcinoma. To explore the expression, regulation and function of DACH1 in human esophageal cancer, 11 esophageal cancer cell lines, 10 cases of normal esophageal mucosa, 51 cases of different grades of dysplasia and 104 cases of primary esophageal squamous cancer were employed. Methylation specific PCR, immunohistochemistry, western blot, flow cytometry, small interfering RNAs, colony formation techniques and xenograft mice model were used. We found that DACH1 expression was regulated by promoter region hypermethylation in esophageal cancer cell lines. 18.8% (6 of 32) of grade 1, 42.1% (8 of 19) of grade 2 and grade 3 dysplasia (ED2,3), and 61.5% (64 of 104) of esophageal cancer were methylated, but no methylation was found in 10 cases of normal esophageal mucosa. The methylation was increased in progression tendency during esophageal carcinogenesis (P<0.01). DACH1 methylation was associated with poor differentiation (P<0.05) and late tumor stage (P<0.05). Restoration of DACH1 expression inhibited cell growth and activated TGF-β signaling in KYSE150 and KYSE510 cells. DACH1 suppressed human esophageal cancer cell tumor growth in xenograft mice. In conclusion, DACH1 is frequently methylated in human esophageal cancer and methylation of DACH1 is involved in the early stage of esophageal carcinogenesis. DACH1 expression is regulated by promoter region hypermethylation. DACH1 suppresses esophageal cancer growth by activating TGF-β signaling.

Could dysregulation of UPS be a common underlying mechanism for cancer and neurodegeneration? Lessons from UCHL1

Ubiquitin proteasome system (UPS) determines the timing and extent of protein turnover in cells, and it is one of the most strictly controlled cellular mechanisms. Lack of proper control over UPS is attributed to both cancer and to neurodegenerative diseases, yet in different context and direction. Cancerous cells have altered cellular metabolisms, uncontrolled cellular division, and increased proteasome activity. The specialized function prevent neurons from undergoing cellular division but allow them to extend an axon over long distances, establish connections, and to form stable neuronal circuitries. Neurons heavily depend on the proper function of the proteasome and the UPS for their proper function. Reduction of UPS function in vulnerable neurons results in protein aggregation, increased ER stress, and cell death. Identification of compounds that selectively block proteasome function in distinct set of malignancies added momentum to drug discovery efforts, and deubiquitinases (DUBs) gained much attention. This review will focus on ubiquitin carboxy-terminal hydrolase L1 (UCHL1), a DUB that is attributed to both cancer and neurodegeneration. The potential of developing effective treatment strategies for two major health problems by controlling the function of UPS opens up new avenues for innovative approaches and therapeutic interventions.

Aberrant DNA Methylation of P16, MGMT, and hMLH1 Genes in Combination with MTHFR C677T Genetic Polymorphism in gastric cancer

OBJECTIVE

We aimed to explore the association of P16, MGMT and HMLH1 with gastric cancer and their relation with Methylenetetrahydrofolate reductase (MTHFR).

METHODS

322 gastric patients who were confirmed with pathological diagnosis were included in our study. Aberrant DNA methylation of P16, MGMT and HMLH1 and polymorphisms of MTHFR C677T and A1298C were detected using PCR-RFLP.

RESULTS

The proportions of DNA hypermethylation in P16, MGMT and hMLH1 genes in gastric cancer tissues were 75.2% (242/322), 27.6% (89/322) and 5.3% (17/322), respectively. In the remote normal-appearing tissues, 29.5% (95/322) and 16.1%(52/322) showed hypermethylation in P16 and MGMT genes, respectively. We found a significantly higher proportion of DNA hypermethylation of P16 in patients with N1 TNM stage in cancer tissues and remote normal-appearing tissues (P<0.05). Similarly, we found DNA hypermethylation of MGMT had significantly higher proportion in N1 and M1 TNM stage (P<0.05). Individuals with homozygotes (TT) of MTHFR C677T had significant risk of DNA hypermethylation of MGMT in cancer tissues [OR (95% CI)=4.27(1.76-7.84)], and a significant risk was also found in those carrying MTHFR 677CT/TT genotype [OR (95% CI)= 3.27(1.21-4.77)].

CONCLUSION

We found the aberrant hypermethylation of cancer-related genes, such as P16, MGMT and HMLH1, could be predictive biomarkers for detection of gastric cancer.

Next-generation sequencing of endoscopic biopsies identifies ARID1A as a tumor-suppressor gene in Barrett's esophagus

The incidence of Barrett's esophagus (BE)-associated esophageal adenocarcinoma (EAC) is increasing. Next-generation sequencing (NGS) provides an unprecedented opportunity to uncover genomic alterations during BE pathogenesis and progression to EAC, but treatment-naive surgical specimens are scarce. The objective of this study was to establish the feasibility of using widely available endoscopic mucosal biopsies for successful NGS, using samples obtained from a BE 'progressor'. Paired-end whole-genome NGS was performed on the Illumina platform using libraries generated from mucosal biopsies of normal squamous epithelium (NSE), BE and EAC obtained from a patient who progressed to adenocarcinoma during endoscopic surveillance. Selective validation studies, including Sanger sequencing, immunohistochemistry and functional assays, were performed to confirm the NGS findings. NGS identified somatic nonsense mutations of AT-rich interactive domain 1A (SWI like) (ARID1A) and PPIE and an additional 37 missense mutations in BE and/or EAC, which were confirmed by Sanger sequencing. ARID1A mutations were detected in 15% (3/20) high-grade dysplasia (HGD)/EAC patients. Immunohistochemistry performed on an independent archival cohort demonstrated ARID1A protein loss in 0% (0/76), 4.9% (2/40), 14.3% (4/28), 16.0% (8/50) and 12.2% (12/98) of NSE, BE, low-grade dysplasia, HGD and EAC tissues, respectively, and was inversely associated with nuclear p53 accumulation (P=0.028). Enhanced cell growth, proliferation and invasion were observed on ARID1A knockdown in EAC cells. In addition, genes downstream of ARID1A that potentially contribute to the ARID1A knockdown phenotype were identified. Our studies establish the feasibility of using mucosal biopsies for NGS, which should enable the comparative analysis of larger 'progressor' versus 'non-progressor' cohorts. Further, we identify ARID1A as a novel tumor-suppressor gene in BE pathogenesis, reiterating the importance of aberrant chromatin in the metaplasia-dysplasia sequence.

Down-regulation of thyroid hormone receptor β1 gene expression in gastric cancer involves promoter methylation

Hypermethylation has been shown in the promoter region of the thyroid hormone receptor β1 (TRβ1) gene in several human tumors. However, its role in gastric cancer formation is still unclear. In the study, we analyzed mRNA expression of TRβ1 gene using real-time quantitative PCR (qPCR). A quantitative methylation-specific PCR (Q-MSP) assay was used to determine the methylation status of the TRβ1 gene promoter region in 46 pair-matched gastric neoplastic and adjacent non-neoplastic tissues. The results showed that TRβ1 mRNA expression was significantly reduced in gastric cancer specimens. The methylation of promoter of TRβ1 gene in gastric cancer tissues was significantly higher than in adjacent normal tissues. Promoter hypermethylation of the TRβ1 gene correlated with tumor infiltration, lymph node metastasis, and distant metastasis, but it was not associated with other clinicopathological characteristics. We treated gastric cancer cell lines MKN-45, MKN-28, SGC-7901, NCI-N87, and SNU-1 with 5-Aza-2-deoxycytidine (5-Aza-dC). The results showed the expression of TRβ1 mRNA was increased in MKN-45, MKN-28, SGC-7901, but not increased in NCI-N87 and SNU-1. These results suggest that the TRβ1 gene plays important roles in the development of gastric cancer partially through epigenetic mechanisms.

Prognostic value of preoperative mean corpuscular volume in esophageal squamous cell carcinoma

AIM: To evaluate whether preoperative mean corpuscular volume (MCV) is a prognostic indicator in patients with resectable esophageal squamous cell carcinoma (ESCC).

METHODS: A total of 298 consecutive, prospectively enrolled patients with histologically diagnosed ESCC who underwent surgery with curative intent from 2001 to 2011 were retrospectively evaluated. Patients were excluded if they had previous malignant disease, distant metastasis at the time of primary treatment, a history of neoadjuvant treatment, had undergone non-radical resection, or had died of a non-tumor-associated cause. Survival status was verified in September 2011. Pathological staging was performed based on the 2010 American Joint Committee on Cancer criteria. Preoperative MCV was obtained from blood counts performed routinely within 7 d prior to surgery. Receiver operating characteristic (ROC) curve analysis was used to determine a cutoff for preoperative MCV.

RESULTS: The 298 patients consisted of 230 males and 68 females, with a median follow-up of 30.1 mo. ROC analysis showed an optimal cutoff for preoperative MCV of 95.6 fl. Fifty-nine patients (19.8%) had high (> 95.6 fl) and 239 (80.2%) had low (≤ 95.6 fl) preoperative MCV. Preoperative MCV was significantly associated with gender (P = 0.003), body mass index (P = 0.017), and preoperative red blood cell count (P < 0.001). The predicted 1-, 3- and 5-year overall survival (OS) rates were 72%, 60% and 52%, respectively. Median OS was significantly longer in patients with low than with high preoperative MCV (27.5 mo vs 19.4 mo, P < 0.001). Multivariate analysis showed that advanced pT (P = 0.018) and pN (P < 0.001) stages, upper thoracic location (P = 0.010), lower preoperative albumin concentration (P = 0.002), and high preoperative MCV (P = 0.001) were negative prognostic factors in patients with ESCC. Preoperative MCV also stratified OS in patients with T3, N1-N3, G2-G3 and stage III tumors.

CONCLUSION: Preoperative MCV is a prognostic factor in patients with ESCC.