Molecular Biology and Clinical Management of Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EAC) is a highly lethal malignancy. Due to its rising incidence, EAC has become a severe health challenge in Western countries. Current treatment strategies are mainly chosen based on disease stage and clinical features, whereas the biological background is hardly considered. In this study, we performed a comprehensive review of existing studies and discussed how etiology, genetics and epigenetic characteristics, together with the tumor microenvironment, contribute to the malignant behavior and dismal prognosis of EAC. During the development of EAC, several intestinal-type proteins and signaling cascades are induced. The anti-inflammatory and immunosuppressive microenvironment is associated with poor survival. The accumulation of somatic mutations at the early phase and chromosomal structural rearrangements at relatively later time points contribute to the dynamic and heterogeneous genetic landscape of EAC. EAC is also characterized by frequent DNA methylation and dysregulation of microRNAs. We summarize the findings of dysregulations of specific cytokines, chemokines and immune cells in the tumor microenvironment and conclude that DNA methylation and microRNAs vary with each different phase of BE, LGD, HGD, early EAC and invasive EAC. Furthermore, we discuss the suitability of the currently employed therapies in the clinic and possible new therapies in the future. The development of targeted and immune therapies has been hampered by the heterogeneous genetic characteristics of EAC. In view of this, the up-to-date knowledge revealed by this work is absolutely important for future EAC studies and the discovery of new therapeutics.

Single domain Camelid antibody fragments for molecular imaging and therapy of cancer

Despite innovations in cancer therapeutics, cancer remains associated with high mortality and is one of biggest health challenges worldwide. Therefore, developing precise cancer imaging and effective treatments is an unmet clinical need. A relatively novel type of therapeutics are heavy chain variable domain antibody fragments (VHHs) derived from llamas. Here, we explored the suitability of VHHs for cancer imaging and therapy through reviewing the existing literature. We searched the MEDLINE, EMBASE and Cochrane databases and identified 32 papers on molecular imaging and 41 papers on therapy that were suitable for comprehensive reviewing. We found that VHHs harbor a higher specificity and affinity compared to mAbs, which contributes to high-quality imaging and less side-effects on healthy cells. The employment of VHHs in cancer imaging showed remarkably shorter times between administration and imaging. Studies showed that 18F and 99mTc are two optimal radionuclides for imaging with VHHs and that site-specific labelling is the optimal conjugation modality for VHHs with radionuclide or fluorescent molecules. We found different solutions for reducing kidney retention and immunogenicity of VHHs. VHHs as anticancer therapeutics have been tested in photodynamic therapy, targeted radionuclide therapy, immunotherapy and molecular targeted therapy. These studies showed that VHHs target unique antigen epitopes, which are distinct from the ones recognized by mAbs. This advantage means that VHHs may be more effective for targeted anticancer therapy and can be combined with mAbs. We found that high cellular internalization and specificity of VHHs contributes to the effectiveness and safety of VHHs as anticancer therapeutics. Two clinical trials have confirmed that VHHs are effective and safe for cancer imaging and therapy. Together, VHHs seem to harbor several advantages compared to mAbs and show potential for application in personalized treatment for cancer patients. VHH-based imaging and therapy are promising options for improving outcomes of cancer patients.

Residual disease after neoadjuvant chemoradiotherapy for oesophageal cancer: locations undetected by endoscopic biopsies in the preSANO trial

Background

Active surveillance has been proposed for patients with oesophageal cancer in whom there is a complete clinical response after neoadjuvant chemoradiotherapy (nCRT). However, endoscopic biopsies have limited negative predictive value in detecting residual disease. This study determined the location of residual tumour following surgery to improve surveillance and endoscopic strategies.

Methods

The present study was based on patients who participated in the prospective preSANO trial with adenocarcinoma or squamous cell carcinoma of the oesophagus or oesophagogastric junction treated in four Dutch hospitals between 2013 and 2016. Resection specimens and endoscopic biopsies taken during clinical response evaluations after nCRT were reviewed by two expert gastrointestinal pathologists. The exact location of residual disease in the oesophageal wall was determined in resection specimens. Endoscopic biopsies were assessed for the presence of structures representing the submucosal layer of the oesophageal wall.

Results

In total, 119 eligible patients underwent clinical response evaluations after nCRT followed by standard surgery. Residual tumour was present in endoscopic biopsies from 70 patients, confirmed on histological analysis of the resected organ. Residual tumour was present in the resection specimen from 27 of the other 49 patients, despite endoscopic biopsies being negative. Of these 27 patients, residual tumour was located in the mucosa in 18, and in the submucosa beneath tumour‐free mucosa in eight. One patient had tumour in muscle beneath tumour‐free mucosa and submucosa.

Conclusion

Most residual disease after nCRT missed by endoscopic biopsies was located in the mucosa. Active surveillance could be improved by more sampling and considering submucosal biopsies.

The Y-chromosome F haplogroup contributes to the development of Barrett's esophagus-associated esophageal adenocarcinoma in a white male population

Barrett's esophagus (BE) is a metaplastic condition of the distal esophagus, resulting from longstanding gastroesophageal reflux disease (GERD). BE predisposes for the highly malignant esophageal adenocarcinoma (EAC). Both BE and EAC have the highest frequencies in white males. Only a subset of patients with GERD develop BE, while <0.5% of BE will progress to EAC. Therefore, it is most likely that the development of BE and EAC is associated with underlying genetic factors. We hypothesized that in white males, Y-chromosomal haplogroups are associated with BE and EAC. To investigate this we conducted a multicenter study studying the frequencies of the Y-chromosomal haplogroups in GERD, BE, and EAC patients. We used genomic analysis by polymerase chain reaction and restriction fragment length polymorphism to determine the frequency of six Y-chromosomal haplogroups (DE, F(xJ,xK), K(xP), J, P(xR1a), and R1a) between GERD, BE, and EAC in a cohort of 1,365 white males, including 612 GERD, 753 BE patients, while 178 of the BE patients also had BE-associated EAC. Univariate logistic regression analysis was used to compare the outcomes. In this study, we found the R1a (6% vs. 9%, P = 0.04) and K (3% vs. 6%, P = 0.035) to be significantly underrepresented in BE patients as compared to GERD patients with an odds ratio (OR) of 0.63 (95% CI 0.42-0.95, P = 0.03) and of 0.56 (95% CI 0.33-0.96, P = 0.03), respectively, while the K haplogroup was protective against EAC (OR 0.30; 95% CI 0.07-0.86, P = 0.05). A significant overrepresentation of the F haplogroup was found in EAC compared to BE and GERD patients (34% vs. 27% and 23%, respectively). The F haplogroup was found to be a risk factor for EAC with an OR of 1.5 (95% CI 1.03-2.19, P = 0.03). We identified the R1a and K haplogroups as protective factors against development of BE. These haplogroups have low frequencies in white male populations. Of importance is that we could link the presence of the predominantly occurring F haplogroup in white males to EAC. It is possible that this F haplogroup is associated to genetic variants that predispose for the EAC development. In future, the haplogroups could be applied to improve stratification of BE and GERD patients with increased risk to develop BE and/or EAC.

The Amsterdam ReBus progressor cohort: identification of 165 Barrett's surveillance patients who progressed to early neoplasia and 723 nonprogressor patients

Patient selection is suboptimal in most studies focused on identifying biological markers for neoplastic progression in Barrett's esophagus (BE). This study aims to describe a stringently selected community-based case-control cohort of non-dysplastic BE (NDBE) patients who progressed to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) and BE patients who never progressed to be used for future biomarker studies. We identified all patients referred for endoscopic work-up of BE neoplasia at three tertiary referral centers for treatment of BE neoplasia between 2000 and 2013. We performed a detailed registration of any endoscopic surveillance history before neoplastic progression. Controls were selected from a retrospective BE surveillance registration in 10 community hospitals. A total of 887 patients were referred for endoscopic work-up of BE neoplasia. Based on predefined selection criteria, we identified 165 progressor patients (82% men; mean age 55 years ± 10.4) with a baseline endoscopy demonstrating NDBE > 2 years before neoplastic progression. Using the same predefined selection criteria, 723 nonprogressor patients (67% men; mean age 57 years ± 11.3) with >2 years of endoscopic surveillance were identified. Median length of the BE segment was 5 cm (IQR 4-7) in progressors and 4 cm (IQR 2-6) in controls. Median duration of surveillance was 89 months (IQR 54-139) in progressors and 76 months (IQR 47-116) in nonprogressors. Paraffin embedded biopsies are available for biomarker research in all patients. Ethical approval was obtained and material transfer agreements were signed with all 58 contributing pathology labs. This is the largest community-based case-control cohort of BE patients with and without progression to early neoplasia. The stringent selection criteria and the availability of paraffin embedded biopsy specimens make this a unique cohort for biomarker studies.

Esophageal sensitivity to acid in patients with Barrett's esophagus is not related to preserved esophageal mucosal integrity

BACKGROUND

Patients with Barrett's esophagus (BE) usually have severe gastroesophageal reflux. However, they often have surprisingly few reflux symptoms. We hypothesized that BE patients are less sensitive to acid than gastroesophageal reflux disease (GERD) patients without Barrett and that this is due to an unusual preservation of mucosal integrity of the squamous epithelium prohibiting transepithelial acid diffusion.

METHODS

We prospectively analyzed esophageal sensitivity and esophageal mucosal integrity in GERD patients with and without BE and healthy subjects. An acid perfusion test was performed and mucosal integrity was assessed in vivo by electrical tissue impedance spectroscopy and ex vivo by Ussing chamber experiments with biopsy specimens.

KEY RESULTS

Gastroesophageal reflux disease patients with BE were less sensitive to acid than GERD patients without BE, but more sensitive to acid than healthy controls (time to perception Barrett's 14.0 minutes, GERD 4.6 minutes, controls 17.5 minutes). However, extracellular impedance (6.2 and 5.7 vs 8.4×10³  Ω/m) and transepithelial resistance (94.0 and 89 vs 118 Ω/cm² ) was similar in BE and GERD patients and significantly lower than in healthy subjects. Transepithelial fluorescein flux was equally increased in GERD patients with and without BE (1.6 and 1.7×10³ vs 0.6×10³  nmol/cm² /h).

CONCLUSIONS & INFERENCES

Esophageal hypersensitivity to acid is less pronounced in BE patients than in GERD patients without Barrett. However, mucosal integrity of the squamous epithelium is equally impaired in GERD patients with and without Barrett, indicating that factors other than esophageal mucosal barrier integrity explain the difference in acid sensitivity between those with BE and those without.

High throughput techniques for characterizing the expression profile of Barrett's esophagus

Barrett's esophagus (BE) is the metaplastic change of the normal lined squamous epithelium of the distal esophagus to a columnar type of epithelium as a result of chronic long-standing gastroesophageal reflux disease. Patients with BE have a significantly increased risk of developing an esophageal adenocarcinoma, with an estimated annual incidence varying from 0.4 to 1.8%. Over the last 3 decades, the incidence of BE and its associated adenocarcinoma has increased in Western countries at a rate that exceeds that of any other malignancy. Despite all the research performed on BE, there is still an inadequate understanding of the biological basis of this mucosal transformation. With the upcoming modern high throughput technologies, important progression has been made in unraveling the expression profiles and gaining more insight in the biology of BE and esophageal adenocarcinoma. Several studies reported genome, transcriptome, proteome, and kinome investigations using high throughput techniques. These studies were conducted to find biomarkers that can be used to detect BE patients with increased risk for malignant progression or to obtain more insight in the mechanism underlying BE development. In the following review, we first discuss the different techniques that are currently available and summarize findings in this field, including several recent publications of our group.

The effect of oral administration of ursodeoxycholic acid and high-dose proton pump inhibitors on the histology of Barrett's esophagus

Bile acids may play a role in the pathogenesis of Barrett's esophagus (BE). Bile composition can be influenced by oral administration of ursodeoxycholic acid (UDCA). We prospectively investigated the effect of proton pump inhibitors (PPI) supplemented with UDCA in vivo in patients with BE. Patients with no or low-grade dysplasia who were clinically asymptomatic on PPI were eligible for the study. In order to exclude the effects of acid reflux, all patients were initially treated with 40 mg esomeprazole (ESO) twice daily for 6 months and continued on this dose till the end of the study (t = 12 months). During a period of 6 months (t = 6 month - t = 12 month) patients were treated with oral UDCA (600 mg twice daily). Patients underwent endoscopy at t = 0 months, t = 6 months and t = 12 months with multiple biopsies of the distal and proximal BE segment, normal squamous and gastric cardia. In addition, pH was measured at t = 0 months and t = 6 months using a BRAVO wireless pH capsule. Bile was sampled at the beginning of the UDCA treatment and 6 months later (t = 6 month and t = 12 month). All biopsies were reviewed for the extent of metaplasia, dysplasia, and acute and chronic inflammation. In addition, proliferation (Ki67), differentiation (villin, cytokeratins 7 and 20) and inflammation (COX-2) were investigated by immunohistochemistry (IHC). Nine patients (mean age 60 years, median BE length 7 cm) were included, of whom six had no dysplasia and three had low-grade dysplasia. pH measurements revealed a normal acid exposure in most patients at t = 0 and t = 6 months. In addition, bile composition analysis demonstrated the efficacy of UDCA. Combining the results of both phases of the study, no significant changes were seen in any of the histological or IHC parameters. Differentiation and proliferation parameters showed no significant changes. In this study, in BE patients who were clinically asymptomatic on PPI, increasing the PPI dose to the maximum for 6 months followed by the addition of UDCA for 6 months did not result in significant histological or IHC changes in their BE.

Stepwise circumferential and focal ablation of Barrett's esophagus with high-grade dysplasia: results of the first prospective series of 11 patients

BACKGROUND AND STUDY AIMS

Stepwise circumferential and focal ablation of nondysplastic Barrett's esophagus has proven safe and effective. This study assessed the efficacy and safety of ablation for Barrett's esophagus with high-grade dysplasia (HGD), and residual Barrett's esophagus with dysplasia after prior endoscopic resection for visible lesions.

PATIENTS AND METHODS

This was a prospective cohort study. All visible abnormalities were resected prior to ablation. Persistence of dysplasia and absence of invasive cancer was confirmed with biopsies after endoscopic resection. A balloon-based electrode was used for primary circumferential ablation and an endoscope-mounted electrode was used for secondary focal ablation. Eradication of dysplasia and Barrett's esophagus was the main outcome measure.

RESULTS

Eleven patients (eight men; median age 60 years) were treated (median Barrett's length 5 cm). Visible abnormalities were removed with endoscopic resection in six patients. The worst pathological grade of residual Barrett's esophagus after endoscopic resection and prior to ablation was LGD (n = 2) and HGD (n = 9). Patients underwent a median of two circumferential and two focal ablation sessions. Complete remission of dysplasia and complete endoscopic and histological removal of Barrett's esophagus was achieved in 11/11 patients (100%). There were no adverse events or strictures, and in none of the 473 biopsies of neo-squamous mucosa was subsquamous Barrett's esophagus ("buried Barrett's") observed. During a median follow-up period of 14 months after the last treatment session and a median number of two follow-up endoscopies, none of the patients showed recurrence of dysplasia or endoscopic signs of recurrent Barrett's mucosa.

CONCLUSIONS

Stepwise circumferential and focal ablation appears to be a safe and effective treatment for complete removal of Barrett's esophagus containing HGD, and can be safely performed after prior endoscopic resection for endoscopically visible abnormalities.

Gene expression profile comparison of Barrett's esophagus epithelial cell cultures and biopsies

Barrett's esophagus (BE) is a metaplastic process in which the normal squamous epithelium of the distal esophagus is replaced by columnar lined epithelium. The aim was to gain more insight in the process of metaplasia and to identify which genes are specifically expressed by the epithelial cells and the surrounding tissues in BE. Hereto, the gene expression profile of a BE epithelial primary cell culture was compared to that of a BE biopsy. To specifically obtain the epithelial cell layer, epithelial cells from biopsies of BE were cultured using a Barrett specific culturing medium. Serial analysis of gene expression was applied to obtain a transcription library of the primary epithelial cell culture. The transcriptome was analyzed and compared to a previously described transcriptome of a BE biopsy. Validation of results by reverse transcriptase-polymerase chain reaction was performed using tissues of 16 BE patients and 16 primary cell cultures. Over 43,000 tags were sequenced. Genes specifically expressed by the Barrett epithelial cells were for instance Lipocalin 2 and Cyclin D1, whereas annexin A10, trefoil factor (TFF)1 and TFF2 were specifically expressed in the BE biopsies. The comparison of the gene expression profiles of BE primary cultured epithelial cells with BE biopsy defines a subset of genes that are specifically expressed by the epithelial cells and another subset that most likely is expressed by the underlying stromal tissues in the BE biopsy specimens.

Surveillance history of endoscopically treated patients with early Barrett's neoplasia: nonadherence to the Seattle biopsy protocol leads to sampling error

The study's aim was to retrospectively evaluate the surveillance history of Barrett's esophagus (BE) patients with endoscopically treated early neoplasia. All BE patients endoscopically treated for early cancer (EC) or high-grade intraepithelial neoplasia (HGIN) in a lesion or mass between 1998 and 2005 were included. Endoscopy and histology records were reviewed. Ninety-four patients (78 males, mean age 67 years, 24 HGIN, 70 EC) were included. In 36 (38%) patients, HGIN/EC was diagnosed at (or within 6 months after) initial endoscopy. The remaining 58 (62%) patients had a surveillance history (median duration 7 years, mean 6.7 endoscopies). Seventy-nine percent of these had low-grade intraepithelial neoplasia (LGIN) diagnosed at least once during their surveillance period with a median of seven endoscopies and a median number of biopsies that was 50% of what should have been taken according to the Seattle protocol. Patients without any dysplasia during earlier surveillance (n = 12, 21%) had undergone significantly less endoscopies (median four endoscopies, P = 0.02) and had a median biopsy percentage that was 23% of the Seattle protocol (P < 0.001 versus 50% in LGIN). In this selected cohort of patients with early Barrett's neoplasia, 38% of patients were diagnosed at initial endoscopy. Of the patients with a surveillance history, 79% had shown LGIN prior to HGIN/EC diagnosis. Only 21% of patients had a surveillance history without any dysplasia, which in general encompassed endoscopies with an insufficient number of biopsies, suggesting sampling error. This underlines the importance of obtaining an adequate number of biopsies during surveillance endoscopies.

Endoscopic cap resection for treatment of early Barrett's neoplasia is safe: a prospective analysis of acute and early complications in 216 procedures

This study aimed to prospectively evaluate the safety of endoscopic resection for early neoplasia in Barrett's esophagus (BE) using the endoscopic cap resection (ER cap) technique. All resections performed between September 2000 and March 2006 with the ER-cap technique in patients with BE were included. Complications were classified 'acute' (during the procedure) or 'early' (< 48 h after the procedure). A total of 216 ER-cap procedures were performed in 121 patients, of which 145 were performed with a standard hard cap and 71 with a large flexible cap. Specimens removed with the standard cap had a mean diameter of 20 mm (SD 5.0) versus 23 mm (SD 5.8) for the large cap (P < 0.001). Acute complications occurred in 51 procedures (24%), 49 bleedings and two perforations. All bleedings were effectively treated with hemostatic techniques and classified as mild complications. No patient experienced a drop in hemoglobin levels or required blood transfusions or repeat interventions. The two perforations were classified as severe complications and treated conservatively. Three (1%) early complications, all bleedings, occurred and were effectively treated with endoscopic hemostatic techniques and classified as moderately severe complications. In manova the indication for the resection (high-grade intraepithelial neoplasia or early cancer versus low-grade intraepithelial neoplasia or no dysplasia) was found to be significantly associated with an increased risk of acute bleeding. Endoscopic cap resection in BE is safe. Most complications become apparent immediately during the procedure and can be managed endoscopically. Bleeding after the endoscopic resection procedure and severe acute complications (i.e., perforations) are rare (2%).

Stepwise radical endoscopic resection of the complete Barrett's esophagus with early neoplasia successfully eradicates pre-existing genetic abnormalities

OBJECTIVES

Malignant transformation of Barrett's mucosa is associated with the accumulation of genetic alterations. Stepwise radical endoscopic resection of the Barrett's segment with early neoplasia is a promising new treatment resulting in complete re-epithelialization of the esophagus with neosquamous epithelium. It is unknown whether radical resection also eradicates genetic abnormalities. The aim of this study was to prospectively evaluate whether genetic abnormalities as found in the Barrett's segment before radical resection are effectively eradicated and absent in the neosquamous epithelium.

METHODS

Nine patients with early neoplasia who successfully underwent radical resection were included. Immunohistochemistry (IHC) was performed to assess p53 protein overexpression. DNA fluorescent in-situ hybridization was (DNA-FISH) performed for evaluation of numerical abnormalities of chromosomes 1 and 9, and losses of p16 and p53. Immunohistochemistry and DNA-FISH were performed on endoscopic resection specimens of the neoplasia and on follow-up biopsies of the neosquamous epithelium.

RESULTS

DNA-FISH and IHC showed alterations in the pretreatment samples of all patients. All showed aneusomy of chromosome 1 and 9. Loss of p16 and p53 were seen in 6 and 8 patients. IHC showed intense p53 nuclear staining in seven patients. Post-treatment biopsies showed neosquamous epithelium with a normal diploid signal count for all DNA-FISH probes and normal IHC stainings in all patients.

CONCLUSIONS

Radical resection of Barrett's esophagus with early neoplasia successfully eradicates pre-existing genetic abnormalities and results in neosquamous epithelium without these genetic abnormalities.

High-resolution endoscopy plus chromoendoscopy or narrow-band imaging in Barrett's esophagus: a prospective randomized crossover study

BACKGROUND AND STUDY AIMS

High-resolution endoscopy (HRE) may improve the detection of early neoplasia in Barrett's esophagus. Indigo carmine chromoendoscopy (ICC) and narrow-band imaging (NBI) may be useful techniques to complement HRE. The aim of this study was to compare HRE-ICC with HRE-NBI for the detection of high-grade dysplasia or early cancer (HGD/EC) in patients with Barrett's esophagus.

PATIENTS AND METHODS

Twenty-eight patients with Barrett's esophagus underwent HRE-ICC and HRE-NBI (separated by 6 - 8 weeks) in a randomized sequence. The two procedures were performed by two different endoscopists, who were blinded to the findings of the other examination. Targeted biopsies were taken from all detected lesions, followed by four-quadrant biopsies at 2-cm intervals. Biopsy evaluation was supervised by a single expert pathologist, who was blinded to the imaging technique used.

RESULTS

Fourteen patients were diagnosed with HGD/EC. The sensitivity for HGD/EC was 93 % and 86 % for HRE-ICC and HRE-NBI, respectively. Targeted biopsies had a sensitivity of 79 % with HRE alone. HGD was diagnosed from random biopsies alone in only one patient. ICC and NBI detected a limited number of additional lesions occult to HRE, but these lesions did not alter the sensitivity for identifying patients with HGD/EC.

CONCLUSIONS

In most patients with high-grade dysplasia or early cancer in Barrett's esophagus, subtle lesions can be identified with high-resolution endoscopy. Indigo carmine chromoendoscopy and narrow-band imaging are comparable as adjuncts to high-resolution endoscopy.

[Barrett's esophagus: new developments in endoscopic surveillance]

The current surveillance strategies for patients with a Barrett's oesophagus are hampered by the poor endoscopic visibility of early neoplastic lesions, the sampling error of random biopsies, the subjectivity of the histological evaluation, and the low incidence of carcinoma. New endoscopic techniques are available for a more reliable evaluation of a Barrett's oesophagus: high-resolution endoscopy, chromoendoscopy, fluorescence endoscopy and optical coherence tomography. The use of molecular markers will probably lead to a better risk stratification of patients. Detection of aneuploid cell populations and assessment of an increase of the number of cells in the S- and G2-phase are possible with DNA flow cytometry; flow cytometric abnormalities may be a more reliable predictor of carcinoma than histological assessment. A combined approach with the new endoscopic techniques and molecular markers may lead to a more efficient and cost-effective surveillance programme.

[Barrett's esophagus: endoscopic treatment of high-grade dysplasia and early cancer]

In a Barrett's oesophagus without dysplasia, endoscopic control every 3-5 years is sufficient. If low-grade dysplasia is encountered in the surveillance biopsies, then endoscopy should be repeated within 3-6 months and yearly thereafter if the low-grade dysplasia persists. Antacid medication must be prescribed in cases with extensive inflammation. The endoscopic treatment of patients with high-grade dysplasia and/or early cancer of the mucosa in a Barrett's oesophagus (tissue ablation and/or mucosa resection) seems a promising alternative to surgery in view of the combination of effectiveness, limited invasiveness compared to surgical resection, and the preservation of a functional oesophagus. Data from long-term follow-up are still limited. Strict endoscopic surveillance will probably detect metachronic abnormalities in an early and still curable stage, creating a new opportunity for endoscopic treatment.

Combined endoscopic mucosal resection and photodynamic therapy for esophageal neoplasia within Barrett's esophagus

BACKGROUND

Endoscopic mucosal resection (EMR) and photodynamic therapy have been proposed as treatments for early stage cancers. EMR is limited by its focal nature whereas photodynamic therapy is dependent on precise staging. The combination of EMR and photodynamic therapy were studied in the treatment of superficial cancer in patients with Barrett's esophagus.

METHODS

Seventeen consecutive nonsurgical patients with superficial cancers underwent EMR followed by photodynamic therapy with a porphyrin photosensitizer. Photoradiation was performed at 630 nm for a total dose of 200 J/cm of diffuser.

RESULTS

Seventeen patients (15 men; mean age 69 +/- 13 years) underwent EMR. The mean diameter of mucosal resection was 1 cm. The margins were involved by cancer in 3 cases. EMR improved staging in 8 patients (47%). Sixteen (94%) patients remained in remission (median follow-up 13 months). Complications included minor bleeding after EMR in 1 patient (6%), stricture in 5 (30%), cutaneous phototoxicity in 2 (12%), and supraventricular tachycardia in 1 patient (6%).

CONCLUSIONS

Combined EMR and photodynamic therapy appears to be an effective and safe therapy for superficial esophageal cancer within Barrett's esophagus. This combination improves cancer staging, removes the superficial cancer, and eliminates remaining mucosa at risk for cancer development.

Extent of high-grade dysplasia in Barrett's esophagus correlates with risk of adenocarcinoma

BACKGROUND & AIMS

The identification of any high-grade dysplasia (HGD) in Barrett's esophagus has been considered to be an indication for esophagectomy because of the increased risk of cancer. The aim of this study was to determine if a limited extent of HGD has the same potential for cancer as diffuse HGD.

METHODS

A retrospective cohort study was performed to assess the risk of developing adenocarcinoma in relationship to the extent of HGD found on endoscopic surveillance. The extent of HGD was defined as focal if cytologic and/or architectural changes of HGD were limited to a single focus of 5 or fewer crypts and diffuse if more than 5 crypts were involved in a single biopsy specimen or if HGD involved more than one biopsy fragment. The relative risk of cancer was assessed using a Cox proportional hazard model, and cancer-free survival was determined using survival curves.

RESULTS

Sixty-seven patients with diffuse HGD and 33 with focal HGD satisfied selection criteria. Cancer-free survival rates at 1 and 3 years were 93% and 86% for focal HGD compared with 62% and 44% for diffuse HGD (P < 0.001). On univariate analysis, extent of HGD (relative risk, 5.36; 95% confidence interval, 1.84-15.56), nodularity on endoscopy (relative risk, 3.98; 95% confidence interval, 1.97-8.04), and lack of acid suppression (relative risk, 2.48; 95% confidence interval, 1.16-5.28) were associated with an increased risk of esophageal adenocarcinoma. Diffuse HGD had a 3.7-fold increase in the risk of esophageal cancer compared with focal HGD (P = 0.02) on multivariate analysis.

CONCLUSIONS

Patients with focal HGD are less likely to have cancer during the first year after diagnosis or on subsequent follow-up compared with diffuse HGD.

Biomarkers in Barrett esophagus

Barrett esophagus is a premalignant condition that may progress to adenocarcinoma. The risk of developing cancer has been estimated to be approximately 1 in 250 patient-years of observation; however, there appear to be subsets of patients at much higher risk. Risk stratification has previously been determined by histological identification of dysplasia. Several new biomarkers are being tested to help clinicians better determine the risk of cancer development. Although none of these biomarkers has been proven in a prospective study to predict the onset of cancer, they have been correlated with cancer development. Most of these are factors that have been associated with cancer development in other organs. These include assessment of cell proliferation, expression of cyclooxygenase 2, growth factors and oncogenes, secretory factors, cell cycle proteins, adhesion molecules, and aneuploidy and other genetic abnormalities. In addition to their role as potential cancer biomarkers, these factors have increasingly been reported as surrogate markers to monitor the effectiveness of conservative treatments for Barrett esophagus. In this article, biological markers are reviewed for their relevance in Barrett esophagus. Although most biological markers need to be evaluated further and, for most, prospective follow-up studies are lacking, at present abnormal ploidy status, P16 and P53 gene abnormalities, or allelic losses are the most extensively documented.

Persistent genetic abnormalities in Barrett's esophagus after photodynamic therapy

BACKGROUND & AIMS

Photodynamic therapy (PDT) is a technique for nonsurgical treatment of patients with dysplasia in Barrett's esophagus. The primary endpoint for PDT has been resolution of dysplasia. We studied the effect of PDT at the genetic level.

METHODS

Archival material from 3 patients who had initial improvement in dysplasia after PDT but occurrence of high-grade dysplasia during follow-up was used. Biopsy specimens were analyzed for increased proliferation, aneuploidy, p53 protein overexpression, p53 mutations, and p16 promoter hypermethylation.

RESULTS

Patients developed high-grade dysplasia 16, 28, and 37 months after PDT. In all cases, one or more genetic markers were positive after PDT treatment, whereas histology was downstaged consistently after therapy. Increasing genetic abnormalities were noted by the end of follow-up.

CONCLUSIONS

Genetic abnormalities may persist after PDT despite phenotypical improvement of dysplasia. These patients may progress to high-grade dysplasia or develop adenocarcinoma. Histologic improvement in dysplasia is an inadequate endpoint for PDT in patients with Barrett's esophagus.

Reduced expression of the cadherin-catenin complex in oesophageal adenocarcinoma correlates with poor prognosis

The E-cadherin-catenin complex is important for cell-cell adhesion of epithelial cells. Impairment of one or more components of this complex is associated with poor differentiation and increased invasiveness of carcinomas. Oesophageal adenocarcinomas causes early metastases, progress rapidly, and consequently have a poor prognosis. By means of immunohistochemistry, the expression of E-cadherin and alpha- and beta-catenin was studied in 65 oesophageal adenocarcinomas and 15 lymph node metastases. Expression of these proteins was evaluated with respect to clinico-pathological parameters and patient survival. Expression of the proteins was strongly correlated. In carcinomas, reduced expression of E-cadherin, alpha-catenin, and beta-catenin was found in 74, 60, and 72 per cent, respectively. Expression of E-cadherin and alpha-catenin correlated significantly with stage and grade of the carcinomas, whereas expression of beta-catenin correlated only with grade. Reduced expression of all three proteins correlated with shorter patient survival. In contrast to grade, E-cadherin and beta-catenin were significant prognosticators for survival, independent of disease stage. We conclude that in oesophageal adenocarcinomas, decreased expression of E-cadherin, alpha-catenin and beta-catenin are related events. Furthermore, expression of at least E-cadherin and beta-catenin is significantly correlated with poor prognosis.

Reduced expression of the cadherin-catenin complex in oesophageal adenocarcinoma correlates with poor prognosis

The E-cadherin-catenin complex is important for cell-cell adhesion of epithelial cells. Impairment of one or more components of this complex is associated with poor differentiation and increased invasiveness of carcinomas. Oesophageal adenocarcinomas causes early metastases, progress rapidly, and consequently have a poor prognosis. By means of immunohistochemistry, the expression of E-cadherin and alpha- and beta-catenin was studied in 65 oesophageal adenocarcinomas and 15 lymph node metastases. Expression of these proteins was evaluated with respect to clinico-pathological parameters and patient survival. Expression of the proteins was strongly correlated. In carcinomas, reduced expression of E-cadherin, alpha-catenin, and beta-catenin was found in 74, 60, and 72 per cent, respectively. Expression of E-cadherin and alpha-catenin correlated significantly with stage and grade of the carcinomas, whereas expression of beta-catenin correlated only with grade. Reduced expression of all three proteins correlated with shorter patient survival. In contrast to grade, E-cadherin and beta-catenin were significant prognosticators for survival, independent of disease stage. We conclude that in oesophageal adenocarcinomas, decreased expression of E-cadherin, alpha-catenin and beta-catenin are related events. Furthermore, expression of at least E-cadherin and beta-catenin is significantly correlated with poor prognosis.

Detection of chromosomal changes by interphase cytogenetics in biopsies of recurrent astrocytomas and oligodendrogliomas

Recently, lineage-specific genetic pathways of tumor progression have been suggested in both oligodendrogliomas and astrocytomas. Aberrations consistently reported in gliomas include chromosomes 1, 7, 10, 17 and 19. Identification of specific genetic damage may have important clinical consequences, because oligodendrogliomas, unlike astrocytomas, are responsive to chemotherapy. Genetic alterations specific for tumor type and tumor progression were investigated in 5 pairs of recurrent astrocytomas and 8 pairs of recurrent oligodendrogliomas by means of interphase in situ hybridization (ISH) to paraffin-embedded, formalin-fixed tissue sections. A set of DNA probes specific for the centromeric regions of chromosomes 1, 7, 10, 17, X and Y was applied. Since LOH studies on oligodendrogliomas have revealed losses in the region of 1p32-1p36, a DNA probe specific for the 1p36.3 locus was included. Hybridization with the 1p36.3 probe revealed loss of 1p in 5 of the 8 oligodendroglioma recurrences, the aberration being present in the primary tumors in 2 cases. In none of the astrocytomas was loss of 1p observed. Numerical aberrations were found in one astrocytoma pair (+7) and in the second biopsy of an oligodendroglioma (+7, -10). Aneuploidy was found by in situ hybridization in 8 of the 13 tumor pairs. Detection of aberrations in the 1p36.3 locus by interphase in situ hybridization to paraffin-embedded, formalin-fixed tumors may become a very useful tool in delineation of oligodendroglial from astrocytic genotypes, directing tumor specific therapy. The technique may be of crucial importance in tumor cases in which histologic criteria of lineage are not obvious.

Reduced expression of the cadherin-catenin complex in oesophageal adenocarcinoma correlates with poor prognosis

The E-cadherin-catenin complex is important for cell-cell adhesion of epithelial cells. Impairment of one or more components of this complex is associated with poor differentiation and increased invasiveness of carcinomas. Oesophageal adenocarcinomas causes early metastases, progress rapidly, and consequently have a poor prognosis. By means of immunohistochemistry, the expression of E-cadherin and alpha- and beta-catenin was studied in 65 oesophageal adenocarcinomas and 15 lymph node metastases. Expression of these proteins was evaluated with respect to clinico-pathological parameters and patient survival. Expression of the proteins was strongly correlated. In carcinomas, reduced expression of E-cadherin, alpha-catenin, and beta-catenin was found in 74, 60, and 72 per cent, respectively. Expression of E-cadherin and alpha-catenin correlated significantly with stage and grade of the carcinomas, whereas expression of beta-catenin correlated only with grade. Reduced expression of all three proteins correlated with shorter patient survival. In contrast to grade, E-cadherin and beta-catenin were significant prognosticators for survival, independent of disease stage. We conclude that in oesophageal adenocarcinomas, decreased expression of E-cadherin, alpha-catenin and beta-catenin are related events. Furthermore, expression of at least E-cadherin and beta-catenin is significantly correlated with poor prognosis.

Prognostic value of the proliferation-related antigen Ki-67 in oligodendrogliomas

BACKGROUND

In various neoplasms expression of the proliferation-related Ki-67 antigen has successfully been linked with parameters of progression of disease. While a definite grading scheme for oligodendrogliomas has still not been agreed upon, any parameter of tumor proliferation that might be helpful in predicting clinical outcome should be evaluated.

METHODS

The expression of the proliferation related nuclear antigen Ki-67 (MIB-1 monoclonal antibody) was investigated in a series of 108 verified oligodendrogliomas, and the percentages of immunoreactive cells were compared with the survival times of the patients. Using multivariate analysis the prognostic value of MIB-1 labeling index (LI) was assessed taking into account age, tumor site, grade, and mitotic index (MI).

RESULTS

Patient's age, tumor site, grading according to the grading scheme by Smith, MI and MIB-1 LI were all significantly related to survival. Whereas in a multivariate analysis, age, site, grade and MIB-1 LI had independent prognostic significance, MI failed to add significant prognostic value.

CONCLUSIONS

The MIB-1 LI is an important addition to histopathologic grading for predicting clinical outcome of patients with oligodendrogliomas. The MIB-1 LI adds prognostic information independent of patient's age, tumor site and grade. The MI might be incorporated into a grading scheme for oligodendrogliomas, but is not by itself an additional prognosticator.

Accumulation of genetic abnormalities during neoplastic progression in Barrett's esophagus

Sex chromosome status, ploidy, and proliferation rate were evaluated in archival material of 73 Barrett's esophagus patients (48 males and 25 females). Diagnosis in esophageal mucosa samples ranged from intestinal metaplasia with no dysplasia to invasive esophageal adenocarcinoma; also, four lymph node metastases were studied. Chromosomal and ploidy aberrations were determined by in situ hybridization with repetitive DNA probes specific for chromosomes Y, X, and 1. Proliferation index (Ki-67 protein expression) was assessed by immunohistochemistry. Proliferation rate was elevated in all stages of dysplasia and in the adenocarcinomas. Aneuploidy (hyperdiploidy) and loss of the Y chromosome correlated with the advancing stages toward neoplasia (P < 0.001) and reached high prevalences (70-100%) in high-grade dysplasia and adenocarcinoma. Abnormalities of the X chromosome were not seen. These data suggest that in Barrett's esophagus, genetic perturbations may be generated in relation to a high proliferation rate.

Accumulation of p53 protein in normal, dysplastic, and neoplastic Barrett's oesophagus

Accumulation of p53 protein was determined by immunohistochemistry in archival material of biopsy specimens from 102 patients with Barrett's oesophagus with different grades of dysplasia, in 24 oesophageal adenocarcinomas associated with Barrett's oesophagus, and in 23 cases of metaplastic epithelium adjacent to these carcinomas. Immunostaining for the p53 protein was found in 23/102 (23 per cent) cases of the Barrett's oesophagus biopsies and in 12/23 (52 per cent) cases of Barrett's oesophagus adjacent to adenocarcinoma. Significant correlations were found between the grade of dysplasia and p53 immunoreactivity in both Barrett's biopsies without adenocarcinoma (P < 0.001) and Barrett's oesophagus adjacent to adenocarcinoma (P < 0.05). In the adenocarcinomas, intense nuclear immunohistochemical staining for p53 was diffusely or focally present in 20/24 (83 per cent) of the specimens. In Barrett's oesophagus, p53 is a progression marker with high expression in high-grade dysplasia (89 per cent) and adenocarcinoma (83 per cent).

Prognostic value of p53 in Barrett's oesophagus

During the last 30 years, the incidence of oesophageal adenocarcinoma has increased rapidly. Patients with Barrett's oesophagus have an increased risk of developing oesophageal adenocarcinoma and should be kept under surveillance. However, only a subset of Barrett's oesophagus patients will eventually develop malignancy and surveillance programs using endoscopy and histopathology cannot efficiently identify this subgroup. The study of additional prognostic factors is therefore of major importance and the p53 tumour suppressor gene has attracted much attention in this respect. Several investigators have found that p53 alteration is a frequent event in oesophageal adenocarcinomas and is associated with malignant transformation of Barrett's oesophagus. p53 appears to be a promising prognostic marker in Barrett's oesophagus and, as research progresses, possible clinical applications are emerging.

Prognostic factors in renal-cell carcinoma: immunohistochemical detection of p53 protein versus clinico-pathological parameters

Immunoreactivity for p53 protein was assessed in 100 cases of primary renal-cell carcinoma (RCC). The results were correlated with clinical survival data (follow-up 24 to 84 months; mean: 39 months) and with clinico-pathological parameters, including nuclear grade, tumour stage, cell type, tumour architecture and tumour diameter. In all, 32% of the tumours were p53-positive; there was no difference in survival between p53-positive and -negative cases. Similarly, p53 expression did not correlate with any of the clinico-pathological parameters mentioned. Nuclear grade (grade 1 + 2 vs. grade 3 + 4) had a striking impact on prognosis and so, to a lesser extent, did tumour stage and the occurrence of a spindle-cell component. The immunohistochemical detection of p53 in RCC is not of prognostic value. The estimation of nuclear grade, however is a major predictor of prognosis.

Detection of genetic changes in Barrett's adenocarcinoma and Barrett's esophagus by DNA in situ hybridization and immunohistochemistry

We have investigated the occurrence of chromosomal DNA and cell cycle-related protein changes in Barrett's epithelium and adenocarcinoma. The presence of numerical chromosomal aberrations was studied by applying nonisotopic in situ hybridization (ISH) with (peri-)centromeric DNA probes, specific for chromosomes 7, 8, 17, and Y, to routinely processed tissue sections of five cases (4 male, 1 female) of Barrett's adenocarcinoma and adjacent Barrett's epithelium. Cell cycle-related protein expression was studied by immunohistochemistry (IHC) for p53 protein and the Ki-67 antigen (Mib-1) in subsequent sections. P53 protein overexpression was found in 3 of the 5 tumors. Overrepresentation of chromosome 8 and loss of chromosome 17 were found in 2 adenocarcinomas, both also negative for p53 protein overexpression. Y-loss, mostly clonal, was detected in 3 of the 4 male adenocarcinomas and 2 cases of adjacent Barrett's epithelium. One tumor had both areas of overrepresentation and loss of the Y chromosome. All Barrett's adenocarcinomas appeared to contain aneuploid cell populations. No relation was found between cell proliferation characteristics and chromosomal aberrations. We conclude that ISH with chromosome specific DNA probes can be applied for the assessment of potentially important numerical chromosome changes in Barrett's esophagus. Further, the combination of IHC and ISH is useful for evaluation of specific genetic events.

Expression of p53 in oligodendrogliomas

The expression of the nuclear protein p53 in oligodendrogliomas was investigated by immunohistochemistry, using a monoclonal anti-p53 antibody (DO-7) on formalin-fixed, paraffin-embedded material in 84 histologically verified cases, and compared with the histopathological grade and survival. p53-immunoreactive cells were found in 75 per cent of the samples acquired at the first biopsy. The p53 labelling index was not related to the degree of nuclear anaplasia. Tumour cases with more than 75 per cent p53 immunostained cells had a rapidly fatal clinical course. However, no significant correlation was found between p53 labelling index and tumour grade, mitotic index, or ploidy status. In most tumour recurrences (n = 25), the p53 labelling index increased or remained at the level of the first biopsy. In five cases (6 per cent), p53 was absent in the first sample as well as in the recurrence. Irrespective of the underlying aberration of either the gene or the metabolic pathway of p53, it is concluded that a high percentage (i.e., more than 75 per cent) of p53-immunolabelled cells is predictive of an unfavourable clinical course, while a percentage lower than 75 per cent immunoreactive cells does not exclude a rapid fatal outcome.