Biomarkers of Barrett's Esophagus: From the Laboratory to Clinical Practice

Diagnosis and Management of Barrett's Esophagus

Barrett's esophagus is a metaplastic change of esophageal mucosa, which can be characterized by its salmon-colored lining and the presence of columnar epithelium with goblet cells. It is a well-established precancerous state of esophageal adenocarcinoma, a tumor with very poor survival rates, which incidence is rapidly growing. Despite numerous research, the debate about its diagnosis and management is still ongoing. This article aims to provide an overview of the current recommendations and new discoveries regarding the subject.

Best Practices in Surveillance for Barrett's Esophagus

Barrett's esophagus is the precursor lesion for esophageal adenocarcinoma. The goals of endoscopic surveillance are to detect dysplasia and early esophageal adenocarcinoma in order to improve patient outcomes. Despite the ongoing debate regarding the efficacy of surveillance, all current gastrointestinal societies recommend surveillance at this time. Optimal surveillance technique includes adequate inspection time, evaluation using high-definition white light and chromoendoscopy, appropriate documentation of the metaplastic segment using the Prague C & M criteria as well as the Paris classification should lesions be found, utilization of the Seattle biopsy protocol, and endoscopic resection of visible lesions.

Endoscopic Eradication Therapy for Barrett's Neoplasia: Where Do We Stand a Decade Later?

PURPOSE OF REVIEW

Barrett's esophagus (BE) is the only known precursor to esophageal adenocarcinoma (EAC), a cancer associated with increasing incidence and poor survival. Early identification and effective treatment of BE-related neoplasia prior to the development of invasive adenocarcinoma are essential to limiting the morbidity and mortality associated with this cancer. In this review, we summarized the recent evidence guiding endoscopic eradication therapies (EET) for neoplastic BE.

RECENT FINDINGS

New sampling technologies and the application of artificial intelligence (AI) systems have potential to revolutionize early neoplasia detection in BE. EET for BE are safe and effective in achieving complete eradication of intestinal metaplasia (CE-IM) and reducing the progression to EAC, a practice endorsed by all GI society guidelines. EET should be considered in patients with high-grade dysplasia (HGD), intramucosal carcinoma (IMC), and select cases with low-grade dysplasia (LGD). The increasing use of endoscopic submucosal dissection (ESD) in the West may allow EET of select cases with submucosal EAC. Post-EET surveillance strategies will continue to evolve as knowledge of specific risk factors and long-term neoplasia recurrence rates improve. In the last decade, major advancements in EET for neoplastic BE have been achieved. These now represent the standard of care in the management of BE-related dysplasia and intramucosal cancer.

Endoscopic eradication therapy for Barrett's oesophagus: state of the art

PURPOSE OF REVIEW

Barrett's oesophagus is the only identifiable precursor lesion to oesophageal adenocarcinoma. The stepwise progression of Barrett's oesophagus to dysplasia and invasive carcinoma provides the opportunity to intervene and reduce the morbidity and mortality associated with this lethal cancer. Several studies have demonstrated the efficacy and safety of endoscopic eradication therapy (EET) for the management of Barrett's oesophagus related neoplasia. The primary goal of EET is to achieve complete eradication of intestinal metaplasia (CE-IM) followed by enrolment of patients in surveillance protocols to detect recurrence of Barrett's oesophagus and Barrett's oesophagus related neoplasia.

RECENT FINDINGS

EET depends on early and accurate detection and diagnosis of Barrett's oesophagus related neoplasia. All visible lesions should be resected followed by ablation of the remaining Barrett's epithelium. After treatment, patients should be enrolled in endoscopic surveillance programmes. For nondysplastic Barrett's oesophagus, surveillance alone is recommended. For low-grade dysplasia, both surveillance and ablation are reasonable options and should be decided on an individual basis according to patient risk factors and preferences. EET is preferred for high-grade dysplasia and intramucosal carcinoma. For T1b oesophageal adenocarcinoma, esophagectomy remains the standard of care, but endoscopic therapy can be considered in select cases.

SUMMARY

EET is now standard of care and endorsed by societal guidelines for the treatment of Barrett's oesophagus related neoplasia. Future studies should focus on risk stratification models using a combination of clinical data and biomarkers to identify ideal candidates for EET, and to predict recurrence. Optimal therapy for T1b cancer and surveillance strategy after CE-IM are topics that require further study.

Circulating microRNA expression profiling revealed miR-92a-3p as a novel biomarker of Barrett's carcinogenesis

The main intent of secondary prevention strategies for Barrett's esophagus (BE) patients relies in the prompt identification of patients with dysplasia (or intra-epithelial neoplasia; IEN) and early-stage adenocarcinoma (Barrett's adenocarcinoma; BAc). Despite the adequate characterization of the molecular landscape characterizing Barrett's carcinogenesis, no tissue and/or circulating biomarker has been approved for clinical use. A series of 25 serum samples (12 BE, 5 HG-IEN and 8 BAc) were analyzed for comprehensive miRNA profiling and ten miRNAs were found to be significantly dysregulated. In particular seven were upregulated (i.e. miR-92a-3p, miR-151a-5p, miR-362-3p, miR-345-3p, miR-619-3p, miR-1260b, and miR-1276) and three downregulated (i.e. miR-381-3p, miR-502-3p, and miR-3615) in HG-IEN/BAc samples in comparison to non-dysplastic BE. All the identified miRNAs showed significant ROC curves in discriminating among groups with AUC values range of 0.75-0.83. Validation of the results were performed by droplet digital PCR in two out of three tested miRNAs. To understand the cellular source of circulating miR-92a-3p, we analyzed its expression in endoscopy biopsy samples by both qRT-PCR and ISH analyses. As observed in serum samples, miR-92a-3p was over-expressed in HG-IEN/BAc samples in comparison to naïve esophageal squamous mucosa and BE and was mainly localized within the epithelial cells, supporting neoplastic cells as the main source of the circulating miRNA. Our data further demonstrated that circulating miRNAs are a promising mini-invasive diagnostic tool in the secondary follow-up and management of BE patients. Larger multi-Institutional studies should validate and investigate the most adequate miRNAs profile in discriminating BE patients in specific risk classes.

Neutrophil-Lymphocyte Ratio as a Marker of Progression from Non-Dysplastic Barrett's Esophagus to Esophageal Adenocarcinoma: a Cross-Sectional Retrospective Study

BACKGROUND

Immune imbalance and inflammation have been suggested as key factors of Barrett's esophagus (BE) pathway towards adenocarcinoma. The neutrophil-lymphocyte ratio (NLR) indirectly reflects the relation between innate and adaptive immune systems and has been studied in premalignant conditions as a biomarker for cancer diagnosis. Our aim was to investigate if increasing values of NLR correlated with advancing stages of BE progression to dysplasia and neoplasia.

METHODS

We retrospectively analyzed data of patients with biopsies reporting BE between 2013 and 2017 and with a complete blood count within 6 months from the endoscopy, as well as patients with esophageal adenocarcinoma (EAC). NLR was calculated as neutrophil count/lymphocyte count. Cases (n = 113) were classified as non-dysplastic BE (NDBE, n = 72), dysplastic BE (DBE, n = 11) and EAC (n = 30).

RESULTS

NLR progressively increased across groups (NDBE, 1.92 ± 0.7; DBE, 2.92 ± 1.1; EAC 4.54 ± 2.9), with a significant correlation between its increasing value and the presence of dysplasia or neoplasia (r = 0.53, p < 0.001). NLR > 2.27 was able to diagnose EAC with 80% sensitivity and 71% specificity (area under the curve = 0.8).

CONCLUSION

NLR correlates with advancing stages of BE progression, a finding that reinforces the role of immune imbalance in EAC carcinogenesis and suggests a possible use of this marker for risk stratification on surveillance strategies.

Proton Pump Inhibitors and Radiofrequency Ablation for Treatment of Barrett's Esophagus

Gastroesophageal Reflux Disease (GERD) is characterized by acid and bile reflux in the distal oesophagus, and this may cause the development of reflux esophagitis and Barrett's oesophagus (BE). The natural histological course of untreated BE is non-dysplastic or benign BE (ND), then lowgrade (LGD) and High-Grade Dysplastic (HGD) BE, with the expected increase in malignancy transfer to oesophagal adenocarcinoma (EAC). The gold standard for BE diagnostics involves high-resolution white-light endoscopy, followed by uniform endoscopy findings description (Prague classification) with biopsy performance according to Seattle protocol. The medical treatment of GERD and BE includes the use of proton pump inhibitors (PPIs) regarding symptoms control. It is noteworthy that long-term use of PPIs increases gastrin level, which can contribute to transfer from BE to EAC, as a result of its effects on the proliferation of BE epithelium. Endoscopy treatment includes a wide range of resection and ablative techniques, such as radio-frequency ablation (RFA), often concomitantly used in everyday endoscopy practice (multimodal therapy). RFA promotes mucosal necrosis of treated oesophagal region via high-frequency energy. Laparoscopic surgery, partial or total fundoplication, is reserved for PPIs and endoscopy indolent patients or in those with progressive disease. This review aims to explain distinct effects of PPIs and RFA modalities, illuminate certain aspects of molecular mechanisms involved, as well as the effects of their concomitant use regarding the treatment of BE and prevention of its transfer to EAC.

Novel biomarkers for risk stratification of Barrett's oesophagus associated neoplastic progression-epithelial HMGB1 expression and stromal lymphocytic phenotype

BACKGROUND

The incidence of oesophageal adenocarcinoma is increasing globally. Barrett's oesophagus (BO) is a pre-malignant condition with no biomarker to risk stratify those at highest risk of dysplasia and malignant transformation.

METHODS

Subcellular epithelial protein (HMGB1, p53, RUNX3) expression, alongside expression of CD20, CD4, CD8 and Foxp3 to characterise stromal B lymphocyte, and helper, cytotoxic and regulatory T-lymphocyte cell infiltrate, respectively, was assessed by immunohistochemistry in 218 human tissue samples including normal oesophageal/gastric biopsies (n = 39), BO (non-dysplasia, dysplasia, non-dysplastic background from progressors to dysplasia or cancer, n = 121) and oesophageal adenocarcinoma (n = 58).

RESULTS

There is a dynamic subcellular epithelial expression of HMGB1 (loss of nuclear, emergence of cytoplasmic), associated with epithelial p53 expression and differential immune cell phenotype in oesophageal neoplastic progression. We identify a protein signature and lymphocyte infiltrate in non-dysplastic BO when progressive disease (dysplasia or adenocarcinoma) is present but not histologically represented in the biopsied field. There is a dynamic stromal lymphocytic infiltrate in oesophageal neoplastic progression.

CONCLUSIONS

This data reveals novel insights into the microenvironment of BO and progression towards cancer and identifies a novel high-risk biomarker of disease progression to aid surveillance strategies to identify early progression and impact future incidence of oesophageal cancer.

Educational Case: Barrett Esophagus

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040.

Evolving screening and surveillance techniques for Barrett's esophagus

Barrett’s esophagus (BE) is a change in the esophageal lining and is known to be the major precursor lesion for most cases of esophageal adenocarcinoma (EAC). Despite an understanding of its association with BE for many years and the falling incidence rates of squamous cell carcinoma of the esophagus, the incidence for EAC continues to rise exponentially. In association with this rising incidence, if the delay in diagnosis of EAC occurs after the onset of symptoms, then the mortality at 5 years is greater than 80%. Appropriate diagnosis and surveillance strategies are therefore vital for BE. Multiple novel optical technologies and other advanced approaches are being utilized to assist in making screening and surveillance more cost effective. We review the current guidelines and evolving techniques that are currently being evaluated.

Biomarker identification and trans-regulatory network analyses in esophageal adenocarcinoma and Barrett’s esophagus

BACKGROUND

Esophageal adenocarcinoma (EAC) is an aggressive disease with high mortality and an overall 5-year survival rate of less than 20%. Barrett’s esophagus (BE) is the only known precursor of EAC, and patients with BE have a persistent and excessive risk of EAC over time. Individuals with BE are up to 30-125 times more likely to develop EAC than the general population. Thus, early detection of EAC and BE could significantly improve the 5-year survival rate of EAC. Due to the limitations of endoscopic surveillance and the lack of clinical risk stratification strategies, molecular biomarkers should be considered and thoroughly investigated.

AIM

To explore the transcriptome changes in the progression from normal esophagus (NE) to BE and EAC.

METHODS

Two datasets from the Gene Expression Omnibus (GEO) in NCBI Database (https://www.ncbi.nlm.nih.gov/geo/) were retrieved and used as a training and a test dataset separately, since NE, BE, and EAC samples were included and the sample sizes were adequate. This study identified differentially expressed genes (DEGs) using the R/Bioconductor project and constructed trans-regulatory networks based on the Transcriptional Regulatory Element Database and Cytoscape software. Enrichment of Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) terms was identified using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) Bioinformatics Resources. The diagnostic potential of certain DEGs was assessed in both datasets.

RESULTS

In the GSE1420 dataset, the number of up-regulated DEGs was larger than that of down-regulated DEGs when comparing EAC vs NE and BE vs NE. Among these DEGs, five differentially expressed transcription factors (DETFs) displayed the same trend in expression across all the comparison groups. Of these five DETFs, E2F3, FOXA2, and HOXB7 were up-regulated, while PAX9 and TFAP2C were down-regulated. Additionally, the majority of the DEGs in trans-regulatory networks were up-regulated. The intersection of these potential DEGs displayed the same direction of changes in expression when comparing the DEGs in the GSE26886 dataset to the DEGs in trans-regulatory networks above. The receiver operating characteristic curve analysis was performed for both datasets and found that TIMP1 and COL1A1 could discriminate EAC from NE tissue, while REG1A, MMP1, and CA2 could distinguish BE from NE tissue. DAVID annotation indicated that COL1A1 and MMP1 could be potent biomarkers for EAC and BE, respectively, since they participate in the majority of the enriched KEGG and GO terms that are important for inflammation and cancer.

CONCLUSION

After the construction and analyses of the trans-regulatory networks in EAC and BE, the results indicate that COL1A1 and MMP1 could be potential biomarkers for EAC and BE, respectively.

Mucin 5B, carbonic anhydrase 9 and claudin 18 are potential theranostic markers of gallbladder carcinoma

AIMS

Gallbladder cancer (GBC) is an aggressive tumour that is usually diagnosed at advanced stages and is characterised by a poor prognosis. Using public data of normal human tissues, we found that mRNA and protein levels of mucin 5B (MUC5B) and carbonic anhydrase 9 (CA9) were highly increased in gallbladder tissues. In addition, previous evidence has shown that claudin 18 (CLDN18) protein expression is higher in GBC. The aim of this study was to perform an analysis of these cell surface proteins during the histological progression of GBC in order to identify their theranostic potential.

METHODS AND RESULTS

MUC5B expression, CA9 expression and CLDN18 expression were examined by immunohistochemistry in a series of 179 chronic cholecystitis (including 16 metaplastic tissues), 15 dysplasia and 217 GBC samples by the use of tissue microarray analysis. A composite staining score was calculated from staining intensity and percentage of positive cells. Immunohistochemical analysis showed high expression of MUC5B and CA9 among normal epithelium, metaplastic tissues, and dysplastic tissues. However, expression of both proteins was observed in roughly 50% of GBC samples. In contrast, CLDN18 was absent in normal epithelium, but its expression was higher in metaplastic cells. Among GBC cases, approximately half showed high CLDN18 expression. No associations were found between MUC5B, CA9 and CLDN18 expression and any clinicopathological features.

CONCLUSIONS

CLDN18 is a new metaplasia marker in gallbladder tissues, and is conserved in approximately half of GBC cases. MUC5B and CA9 are highly conserved during GBC histological progression. The three markers are potential theranostic markers, in particular CA9 and CLDN18, for which there are already targeted therapies available.

Ex vivo drug sensitivity testing as a means for drug repurposing in esophageal adenocarcinoma

Background

Esophageal cancer remains one of the hardest cancers to treat with rising incidence rates, low overall survival and high levels of treatment resistance. The lack of clinically available biomarkers hinder diagnosis and treatment stratification. While large scale sequencing approaches have uncovered a number of molecular makers, little has translated in the routine treatment of esophageal cancer patients.

Material and methods

We evaluate the treatment response towards a panel of 215 FDA-approved and 163 epigenetic compounds of 4 established and 2 patient-derived esophageal cancer cell lines. Cell viability was evaluated after 72h of treatment using cell titer glow. The drug sensitivity testing results for gemcitabine and cisplatin were validated using clonogenic assays.

Results

The tested cell lines display different drug sensitivity profiles, although we found compounds that display efficacy in all of the tested established or patient-derived cell lines. Clonogenic assays confirmed the validity of the drug sensitivity testing results. Using the epigenetic library, we observed high sensitivity towards a number of epigenetic modifiers.

Discussion

Ex vivo drug sensitivity testing may present a viable option for the treatment stratification of esophageal cancer patients and holds the potential to greatly improve patient outcome while reducing treatment toxicity.