Clinical decision making in Barrett's oesophagus can be supported by computerized immunoquantitation and morphometry of features associated with proliferation and differentiation

Barrett's esophagus: The pathomorphological and molecular genetic keystones of neoplastic progression

Barrett's esophagus is a widespread chronically progressing disease of heterogeneous nature. A life threatening complication of this condition is neoplastic transformation, which is often overlooked due to lack of standardized approaches in diagnosis, preventative measures and treatment. In this essay, we aim to stratify existing data to show specific associations between neoplastic transformation and the underlying processes which predate cancerous transition. We discuss pathomorphological, genetic, epigenetic, molecular and immunohistochemical methods related to neoplasia detection on the basis of Barrett's esophagus. Our review sheds light on pathways of such neoplastic progression in the distal esophagus, providing valuable insight into progression assessment, preventative targets and treatment modalities. Our results suggest that molecular, genetic and epigenetic alterations in the esophagus arise earlier than cancerous transformation, meaning the discussed targets can help form preventative strategies in at-risk patient groups.

Cell Image Classification: A Comparative Overview

Cell image classification methods are currently being used in numerous applications in cell biology and medicine. Applications include understanding the effects of genes and drugs in screening experiments, understanding the role and subcellular localization of different proteins, as well as diagnosis and prognosis of cancer from images acquired using cytological and histological techniques. The article also reviews three main approaches for cell image classification most often used: numerical feature extraction, end-to-end classification with neural networks (NNs), and transport-based morphometry (TBM). In addition, we provide comparisons on four different cell imaging datasets to highlight the relative strength of each method. The results computed using four publicly available datasets show that numerical features tend to carry the best discriminative information for most of the classification tasks. Results also show that NN-based methods produce state-of-the-art results in the dataset that contains a relatively large number of training samples. Data augmentation or the choice of a more recently reported architecture does not necessarily improve the classification performance of NNs in the datasets with limited number of training samples. If understanding and visualization are desired aspects, TBM methods can offer the ability to invert classification functions, and thus can aid in the interpretation of results. These and other comparison outcomes are discussed with the aim of clarifying the advantages and disadvantages of each method. © 2020 International Society for Advancement of Cytometry.

Adherence to pre-set benchmark quality criteria to qualify as expert assessor of dysplasia in Barrett's esophagus biopsies - towards digital review of Barrett's esophagus

Background

Dysplasia assessment of Barrett’s esophagus biopsies is associated with low observer agreement; guidelines advise expert review. We have developed a web-based review panel for dysplastic Barrett’s esophagus biopsies.

Objective

The purpose of this study was to test if 10 gastrointestinal pathologists working at Dutch Barrett’s esophagus expert centres met pre-set benchmark scores for quality criteria.

Methods

Ten gastrointestinal pathologists twice assessed 60 digitalized Barrett’s esophagus cases, enriched for dysplasia; then randomised (7520 assessments). We tested predefined benchmark quality criteria: (a) percentage of ‘indefinite for dysplasia’ diagnoses, benchmark score ≤14% for all cases, ≤16% for dysplastic subset, (b) intra-observer agreement; benchmark score ≥0.66/≥0.39, (c) percentage agreement with ‘gold standard diagnosis’; benchmark score ≥82%/≥73%, (d) proportion of cases with high-grade dysplasia underdiagnosed as non-dysplastic Barrett’s esophagus; benchmark score ≤1/78 (≤1.28%) assessments for dysplastic subset.

Results

Gastrointestinal pathologists had seven years’ Barrett’s esophagus-experience, handling seven Barrett’s esophagus-cases weekly. Three met stringent benchmark scores; all cases and dysplastic subset, three met extended benchmark scores. Four pathologists lacked one quality criterion to meet benchmark scores.

Conclusion

Predefined benchmark scores for expert assessment of Barrett’s esophagus dysplasia biopsies are stringent and met by some gastrointestinal pathologists. The majority of assessors however, only showed limited deviation from benchmark scores. We expect further training with group discussions will lead to adherence of all participating gastrointestinal pathologists to quality criteria, and therefore eligible to join the review panel.

Development of benchmark quality criteria for assessing whole-endoscopy Barrett's esophagus biopsy cases

Background

Dysplasia in Barrett's esophagus (BE) biopsies is associated with low observer agreement among general pathologists. Therefore, expert review is advised. We are developing a web-based, national expert review panel for histological review of BE biopsies.

Objective

The aim of this study was to create benchmark quality criteria for future members.

Methods

Five expert BE pathologists, with 10–30 years of BE experience, weekly handling 5–10 cases (25% dysplastic), assessed a case set of 60 digitalized cases, enriched for dysplasia. Each case contained all slides from one endoscopy (non-dysplastic BE (NDBE), n = 21; low-grade dysplasia (LGD), n = 20; high-grade dysplasia (HGD), n = 19). All cases were randomized and assessed twice followed by group discussions to create a consensus diagnosis. Outcome measures: percentage of ‘indefinite for dysplasia’ (IND) diagnoses, intra-observer agreement, and agreement with the consensus ‘gold standard’ diagnosis.

Results

Mean percentage of IND diagnoses was 8% (3–14%) and mean intra-observer agreement was 0.84 (0.66–1.02). Mean agreement with the consensus diagnosis was 90% (95% prediction interval (PI) 82–98%).

Conclusion

Expert pathology review of BE requires the scoring of a limited number of IND cases, consistency of assessment and a high agreement with a consensus gold standard diagnosis. These benchmark quality criteria will be used to assess the performance of other pathologists joining our panel.

Digital microscopy as valid alternative to conventional microscopy for histological evaluation of Barrett's esophagus biopsies

Management of Barrett's esophagus (BE) relies heavily on histopathological assessment of biopsies, associated with significant intra- and interobserver variability. Guidelines recommend biopsy review by an expert in case of dysplasia. Conventional review of biopsies, however, is impractical and does not allow for teleconferencing or annotations. An expert digital review platform might overcome these limitations. We compared diagnostic agreement of digital and conventional microscopy for diagnosing BE ± dysplasia. Sixty BE biopsy glass slides (non-dysplastic BE (NDBE); n = 25, low-grade dysplasia (LGD); n = 20; high-grade dysplasia (HGD); n = 15) were scanned at ×20 magnification. The slides were assessed four times by five expert BE pathologists, all practicing histopathologists (range: 5-30 years), in 2 alternating rounds of digital and conventional microscopy, each in randomized order and sequence of slides. Intraobserver and pairwise interobserver agreement were calculated, using custom weighted Cohen's kappa, adjusted for the maximum possible kappa scores. Split into three categories (NDBE, IND, LGD+HGD), the mean intraobserver agreement was 0.75 and 0.84 for digital and conventional assessment, respectively (p = 0.35). Mean pairwise interobserver agreement was 0.80 for digital and 0.85 for conventional microscopy (p = 0.17). In 47/60 (78%) of digital microscopy reviews a majority vote of ≥3 pathologists was reached before consensus meeting. After group discussion, a majority vote was achieved in all cases (60/60). Diagnostic agreement of digital microscopy is comparable to that of conventional microscopy. These outcomes justify the use of digital slides in a nationwide, web-based BE revision platform in the Netherlands. This will overcome the practical issues associated with conventional histologic review by multiple pathologists.

Advanced precancerous lesions within the GI tract: the molecular background

The mainstream carcinogenic processes involved within the gastrointestinal tract are characterized by phenotypic multistep progression cascades that eventually result in full-blown cancers. In this scenario, the understanding of the molecular dysregulations underlying the precancerous lesions is increasing but still remains incomplete. However, in recent years, the enthusiastic rise of innovative technologies (i.e., next-generation sequencing, high-throughput microarray analysis, mass spectrometry based proteomics) and the unexpected discovery of new classes of biomarkers (i.e., miRNA, long-noncoding RNAs) prompted new strength in the exploration of the accurate and comprehensive molecular characterization of premalignant and malignant neoplastic lesions. The challenge ahead lies in the reliable identification of disease progression-specific targets to enable molecular testing in the clinical management of the secondary prevention of gastrointestinal cancers.

[Subjective grading of Barrett's neoplasia by pathologists: correlation with objective histomorphometric variables]

Even though pathologists are trained to recognize the same histological features for the diagnosis and grading of different histological images, not all pathologists are influenced to a similar level of intensity by the same morphological characteristics of the tissue when scoring Barrett's dysplasia/neoplasia. The variables which most pathologists have intuitively chosen to use for scoring of the severity of Barrett's changes are mainly those related to the general tissue architecture, such as nuclear crowding, orientation and stratification. Interestingly, nuclear size is not used by most pathologists but nuclear pleomorphism and symmetry does influence a significant number of pathologists. Maybe the most difficult variables for the human eye to recognize are variables of chromatin texture (such as margination or heterogeneity), the predictive importance of which has been demonstrated in a previously published work. Textural variables may therefore remain the subject of a computerized analysis. Nevertheless, the fact that a few pathologists do actually correlate with nuclear texture in scoring, argues in favor of making further attempts to train pathologists to also rely on texture, similar to cytologists, when scoring Barrett's dysplasia.

Predictors for neoplastic progression in patients with Barrett's Esophagus: a prospective cohort study

OBJECTIVES

Patients with Barrett's esophagus (BE) have an increased risk of developing esophageal adenocarcinoma (EAC). As the absolute risk remains low, there is a need for predictors of neoplastic progression to tailor more individualized surveillance programs. The aim of this study was to identify such predictors of progression to high-grade dysplasia (HGD) and EAC in patients with BE after 4 years of surveillance and to develop a prediction model based on these factors.

METHODS

We included 713 patients with BE (≥ 2 cm) with no dysplasia (ND) or low-grade dysplasia (LGD) in a multicenter, prospective cohort study. Data on age, gender, body mass index (BMI), reflux symptoms, tobacco and alcohol use, medication use, upper gastrointestinal (GI) endoscopy findings, and histology were prospectively collected. As part of this study, patients with ND underwent surveillance every 2 years, whereas those with LGD were followed on a yearly basis. Log linear regression analysis was performed to identify risk factors associated with the development of HGD or EAC during surveillance.

RESULTS

After 4 years of follow-up, 26/713 (3.4%) patients developed HGD or EAC, with the remaining 687 patients remaining stable with ND or LGD. Multivariable analysis showed that a known duration of BE of ≥ 10 years (risk ratio (RR) 3.2; 95% confidence interval (CI) 1.3-7.8), length of BE (RR 1.11 per cm increase in length; 95% CI 1.01-1.2), esophagitis (RR 3.5; 95% CI 1.3-9.5), and LGD (RR 9.7; 95% CI 4.4-21.5) were significant predictors of progression to HGD or EAC. In a prediction model, we found that the annual risk of developing HGD or EAC in BE varied between 0.3% and up to 40%. Patients with ND and no other risk factors had the lowest risk of developing HGD or EAC (<1%), whereas those with LGD and at least one other risk factor had the highest risk of neoplastic progression (18-40%).

CONCLUSIONS

In patients with BE, the risk of developing HGD or EAC is predominantly determined by the presence of LGD, a known duration of BE of ≥10 years, longer length of BE, and presence of esophagitis. One or combinations of these risk factors are able to identify patients with a low or high risk of neoplastic progression and could therefore be used to individualize surveillance intervals in BE.

Low-grade dysplasia in Barrett's esophagus: overdiagnosed and underestimated

OBJECTIVES

Published data on the natural history of low-grade dysplasia (LGD) in Barrett's esophagus (BE) are inconsistent and difficult to interpret. We investigated the natural history of LGD in a large community-based cohort of BE patients after reviewing the original histological diagnosis by an expert panel of pathologists.

METHODS

Histopathology reports of all patients diagnosed with LGD between 2000 and 2006 in six non-university hospitals were reviewed by two expert pathologists. This panel diagnosis was subsequently compared with the histological outcome during prospective endoscopic follow-up.

RESULTS

A diagnosis of LGD was made in 147 patients. After pathology review, 85% of the patients were downstaged to non-dysplastic BE (NDBE) or to indefinite for dysplasia. In only 15% of the patients was the initial diagnosis LGD. Endoscopic follow-up was carried out in 83.6% of patients, with a mean follow-up of 51.1 months. For patients with a consensus diagnosis of LGD, the cumulative risk of progressing to high-grade dysplasia or carcinoma (HGD or Ca) was 85.0% in 109.1 months compared with 4.6% in 107.4 months for patients downstaged to NDBE (P<0.0001). The incidence rate of HGD or Ca was 13.4% per patient per year for patients in whom the diagnosis of LGD was confirmed. For patients downstaged to NDBE, the corresponding incidence rate was 0.49%.

CONCLUSIONS

LGD in BE is an overdiagnosed and yet underestimated entity in general practice. Patients diagnosed with LGD should undergo an expert pathology review to purify this group. In case the diagnosis of LGD is confirmed, patients should undergo strict endoscopic follow-up or should be considered for endoscopic ablation therapy.

Computerized morphometry as an aid in determining the grade of dysplasia and progression to adenocarcinoma in Barrett's esophagus

The aims of this study were to use computerized morphometry in order to differentiate between the degree of dysplasia and to predict progression to invasive adenocarcinoma in Barrett's esophagus (BE). Biopsies from 97 patients with BE graded by a consensus forum of expert gastrointestinal pathologists were available for morphometrical analysis. The study group included 36 biopsies negative for dysplasia (ND), none of which progressed to carcinoma; 16 indefinite for dysplasia (IND) and 21 low-grade dysplasia (LGD), of which three progressed in each group and 24 high-grade dysplasia (HGD), of which 15 progressed to invasive carcinoma. Computerized morphometry was used for measuring indices of size, shape, texture, symmetry and architectural distribution of the epithelial nuclei. Low-grade dysplasia was best differentiated from the ND group by nuclear pseudostratification (P=0.036), pleomorphism (P<0.01), and chromatin texture (margination, P<0.01) and from the HGD group by nuclear area (P<0.01), pleomorphism (P<0.01), chromatin texture (margination, P<0.01), symmetry (P<0.01), and orientation (P=0.027). These results were validated on a new set of cases (n=55) using a neural network model, resulting in an accuracy of 89% for differentiating between the ND and LGD groups and 86% for differentiating between the LGD and HGD groups. Within the HGD group, univariate significant predictors of the progression interval to carcinoma were: indices of nuclear texture (heterogeneity: P=0.0019, s.d.-OD: P=0.005) and orientation: P=0.022. Nuclear texture (heterogeneity) was the only independent predictor of progression (P=0.004, hazard=11.54) by Cox's multivariate test. This study proposes that computerized morphometry is a valid tool for determining the grade of dysplasia in BE. Moreover, histomorphometric quantification of nuclear texture is a powerful tool for predicting progression to invasive adenocarcinoma in patients with HGD.

Genetic mechanisms of TP53 loss of heterozygosity in Barrett's esophagus: implications for biomarker validation

BACKGROUND AND AIMS

17p (TP53) loss of heterozygosity (LOH) has been reported to be predictive of progression from Barrett's esophagus to esophageal adenocarcinoma, but the mechanism by which TP53 LOH develops is unknown. It could be (a) DNA deletion, (b) LOH without copy number change, or (c) tetraploidy followed by genetic loss. If an alternative biomarker assay, such as fluorescence in situ hybridization (FISH), provided equivalent results, then translation to the clinic might be accelerated, because LOH genotyping is presently limited to research centers.

METHODS

We evaluated mechanisms of TP53 LOH to determine if FISH and TP53 LOH provided equivalent results on the same flow-sorted samples (n = 43) representing established stages of clonal progression (diploid, diploid with TP53 LOH, aneuploid) in 19 esophagectomy specimens.

RESULTS

LOH developed by all three mechanisms: 32% had DNA deletions, 32% had no copy number change, and 37% had FISH patterns consistent with a tetraploid intermediate followed by genetic loss. Thus, FISH and LOH are not equivalent (P < 0.000001).

CONCLUSIONS

LOH develops by multiple chromosome mechanisms in Barrett's esophagus, all of which can be detected by genotyping. FISH cannot detect LOH without copy number change, and dual-probe FISH is required to detect the complex genetic changes associated with a tetraploid intermediate. Alternative biomarker assay development should be guided by appreciation and evaluation of the biological mechanisms generating the biomarker abnormality to detect potential sources of discordance. FISH will require validation in adequately powered longitudinal studies before implementation as a clinical diagnostic for esophageal adenocarcinoma risk prediction.

Advances in cancer tissue microarray technology: Towards improved understanding and diagnostics

Over the past few years, tissue microarray (TMA) technology has been established as a standard method for assessing the expression of proteins or genes across large sets of tissue specimens. It is being adopted increasingly among leading research institutions around the world and utilized in cancer research in parallel with the cDNA microarray technology. This article summarizes various aspects of cancer understanding and diagnostics in which TMA has had great impact. Although tremendous advances continue to be made to facilitate imaging and archiving of TMA specimens, automatic evaluation and quantitative analysis of TMA still remains an important challenge for modern investigators.

O critério de positividade para a análise imunoistoquímica da p53 na confirmação da displasia do esôfago de Barrett faz diferença?

RACIONAL: O esôfago de Barrett é uma complicação da doença do refluxo gastroesofágico com importante potencial de malignização. Relata-se que a expressão do marcador tumoral p53 se acentua com a progressão displasia-adenocarcinoma. OBJETIVO: Avaliar a expressão da p53 no epitélio de Barrett com presença ou não de displasia conforme dois critérios de positividade. MATERIAL E MÉTODOS: O material foi constituído por biopsias endoscópicas de 42 doentes com esôfago de Barrett. Cortes histológicos foram corados pela hematoxilina-eosina, pelo PAS-alcian blue e avaliados quanto à expressão imunoistoquímica da p53. O diagnóstico de displasia foi firmado pela concordância entre três patologistas. Foram utilizados dois critérios de positividade para a p53: 1. a coloração de, pelo menos, metade dos núcleos e 2. o encontro de qualquer núcleo corado. RESULTADOS: O número total de fragmentos foi de 229, com média de 5,4 por paciente. A displasia foi detectada em seis (14,3%) casos. Para diferentes critérios de positividade, a p53 foi detectada, respectivamente, em 5 (13,9%) e 14 (38,9%) com epitélio metaplásico não-displásico. Especificamente nos seis casos displásicos, a p53 foi detectada, conforme o critério de positividade, em um (16,7%) e quatro (66,7%) casos, respectivamente. CONCLUSÕES: Nesta pequena série, a expressão imunoistoquímica da p53, independente do critério de positividade, não foi de auxílio para a confirmação de alterações displásicas no esôfago de Barrett.

Gastroesophageal reflux and cancer

The causal relationship between GERD and esophageal adenocarcinoma, although unclear just a few decades ago, now is established fairly well. The physiologic changes and the biocellular alterations of the damaged esophageal mucosa are documented better. Despite this knowledge, the dramatic increase in the incidence of esophageal cancer cannot be explained. The absolute risk of esophageal adenocarcinoma arising from GERD is low, and, at present, does not justify population-screening programs. Still, with the notion that adenocarcinoma of the esophagus is an aggressive cancer once documented, important questions still are in need of answers for patients suffering from reflux symptoms. Patients who have reflux disease are not necessarily symptomatic. It remains unclear if patients experiencing reflux symptoms should undergo mandatory endoscopy with biopsies at the esophagogastric junction. Furthermore, metaplasia of the lower esophagus often is not readily recognizable at endoscopy, and only biopsies can document abnormal histology. A severe and prolonged history of reflux always should orient to the possibility of a reflux-related columnar-lined esophagus. Once documented, Barrett's esophagus needs to be seen as a premalignant condition not necessarily leading to adenocarcinoma formation; despite their increased risk of tumor formation, most patients who have Barrett's esophagus die of other causes. During regular endoscopic follow-up, multilevel circumferential biopsies should document the evolution of the histologic changes in the lower esophagus and at the gastroesophageal junction of these patients. It is the only method available to document the appearance of dysplasia. It still is unclear if medicine or surgery provides the best quality of life and the best protection against the development of dysplasia and the possible progression toward adenocarcinoma formation when intestinal metaplasia is present in the esophagus.

Biomarkers in Barrett's esophagus

This article provides a framework for clinicians who are attempting the difficult task of interpreting the Barrett's biomarker literature with the goal of improving care for their patients. Although many articles. including more that 60 proposed biomarkers, have been published on this subject, only a few describe phase 3 and 4 studies that are of interest to the clinical gastroenterologist (Table 1). For year, dysplasia grade has been the sole means of risk stratification for patients with BE, and it likely will continue to be used in the foreseeable future. The current authors believe that dysplasia classification can be valuable using the team management approach and quality controls described previously. Significant problems, however, have emerged in phase 2 through 4 studies of dysplasia that make it imperative for the Barrett's field to incorporate additional biomarkers as they are validated. These problems include poor reproducibility of dysplasia interpretations, poor predictive value for negative, indefinite, and low-grade dysplasia, and inconsistent results for HGD in different centers, all of which makes it virtually impossible to develop national guidelines for surveillance. Some studies have even suggested that endoscopic biopsy surveillance using dysplasia may not be worthwhile. Currently, flow cytometric tetraploidy and aneuploidy have progressed furthest in biomarker validation (see Table 1). With proper handling, endoscopic biopsy specimens can be shipped to reference laboratories that have the instruments, computer analytic methods, and expertise to reproducibly detect tetraploidy and aneuploidy. The results of phase 4 studies indicate that flow cytometry appears to be useful in detecting a subset of patients who do not have HGD and yet have an increased risk of progression to cancer that cannot be identified by dysplasia grade. For many reasons, the authors anticipate that the number of validated biomarkers will increase substantially in the future. Biopsy repositories are now readily available for phase 3 studies that can evaluate and compare biomarkers. There are initiatives for multi-institutional Barrett's Centers of Excellence that could provide rapid progress in biomarker evaluation. In addition to new candidate biomarkers, the human genome project has provided high-throughput methodologies and methods for computer analysis of data, which can provide the volume and quality control required for clinically useful biomarkers. Currently, 17p (p53) LOH has progressed the furthest among molecular biomarkers. The authors do not recommend its routine clinical use at the present time, however. Finally, it is likely that clinicians will want to follow the results of clinical treatment-response studies and epidemiologic studies that evaluate relationship between clinical interventions or environmental risk and protective factors and surrogate endpoints, especially if the endpoints are progessing well along the phases of biomarker validation. These studies are likely to be of clinical interest because they may becoming the basis for randomized clinical trials to prevent cancer in BE.

Routine morphometrical analysis can improve reproducibility of dysplasia grade in Barrett's oesophagus surveillance biopsies

BACKGROUND

The grade of dysplasia found in Barrett's oesophagus surveillance biopsies is a major factor to determine follow up and treatment. However, it has been reported that the reproducibility of the grading system is not optimal.

AIMS

To compare routine and expert dysplasia grades in Barrett's oesophagus surveillance biopsies. To evaluate prospectively morphometrical grading support and to assess the pitfalls in its daily application.

METHODS

Consecutive biopsies (n = 143) were graded routinely by experienced general surgical pathologists as no dysplasia (ND), indefinite for dysplasia, low grade dysplasia (LGD), and high grade dysplasia (HGD). Two expert gastrointestinal pathologists blindly reviewed all sections. The stratification index of nuclei, mean nuclear area, and Ki67area% were assessed routinely according to a strict protocol. With these features, the previously described morphometrical grade was calculated for each case. The grades provided by the experts, surgical pathologists, and morphometry were compared.

RESULTS

The general pathologists graded many more cases as dysplastic than did the experts. Complete agreement between the experts' grades and the original grades was 50 of 143 (35%). Sixty four of the 71 original LGDs and 11 of the 23 original HGDs were downgraded by the experts, whereas one LGD was upgraded. In 93 of the 143 biopsies, at review pitfalls or special characteristics of a technical nature (tangential cutting, severe inflammation, ulcer or the squamocylindrical junction very close by, among others) were seen in the part of the biopsy marked as diagnostic. These probably contributed in part to the original overdiagnoses and could have been prevented or corrected. The morphometrical grading model has not been developed to compensate for this; application of the current morphometrical grading method is not allowed and may result in erroneous (usually too high) morphometrical grades. In spite of this, all HGDs according to the experts were recognised as such by morphometry, also in these technically less adequate sections or areas. However, 46% of the experts' downgrades occurred in technically adequate sections and thus were caused by a difference in interpretation. Here, morphometrical support proved to be useful because, in agreement with the experts, it downgraded 51% of the original LGDs, upgraded one of eight NDs to LGD and one of 39 LGDs to HGD.

CONCLUSIONS

Experts downgraded a high proportion of biopsies graded as LGDs and HGDs by the surgical pathologists. Morphometrical grading can be used for daily quality control; the results were close to those of the experts and corrected a large number of cases erroneously graded by surgical pathologists.

The framework of pathology: good laboratory practice by quantitative and molecular methods

Combined confocal laser scan microscopy (CLSM) and Fourier analysis (FA) by non-pathologists of dermal collagen bundle orientation recently gave results superior to subjective evaluation by experts. According to Good Laboratory Practice (GLP) criteria, combined CLSM/FA has not yet been adequately tested to replace current collagen evaluation, but this will not take long. Non-pathologists (clinicians) will then have taken over a laboratory test historically belonging to pathology. A general trend in this direction may develop, because pathologists seem not always to care enough about clinical significance, reproducibility and prognostic value, and new demands for innovative methods. Quantitative image analysis (QIA) and molecular methods are reproducible, inexpensive, and easy to perform; they often have greater value than classical evaluations and their cost-benefit ratio is good. However, their acceptance is not as widespread as one would expect and theoretical reasons which have been advanced do not provide a satisfactory explanation. A formal implementation study was therefore performed, in which an attempt was made to modernize a classical pathology laboratory. An external customer satisfaction investigation showed that 96% of the clinicians were 'very satisfied' (the highest rating possible) with the completed innovations, contrasting with low satisfaction at the beginning. Lack of primary innovative leadership among pathologists was judged to be the dominant cause preventing implementation. Pathologists should focus on carefully reacting to new clinical needs, using GLP criteria. Reproducibility and predictive accuracy should be major themes in any pathology practice.

Histologic precursors of gastrointestinal tract malignancy

Precursor lesions in the GIT include flat dysplasias, adenomas, dysplasia superimposed on nonneoplastic polyps, endocrine cell dysplasia, ACF, and condyloma accuminatum. Interobserver variability can be a problem in reporting dysplasia, and ancillary techniques including flow cytometry, image analysis, proliferation markers, and examination for p53 expression can help in this task. Squamous dysplasia seen in the esophagus and anus is graded on either a two-tiered or three-tiered system largely based on the extent of mucosal involvement. Glandular dysplasia is morphologically similar whether seen as an adenomatous polyp or within the setting of Barrett's esophagus, atrophic gastritis, or idiopathic inflammatory bowel disease. The distinction between LGD and HGD in glandular mucosa is based on the severity of cytologic and architectural distortion. Type I dysplasia is the classic adenomatous pattern seen most commonly and recognized by the presence of elongate hyperchromatic stratified nuclei. Type II, the nonadenomatous variant, contains vesicular nuclei and alteration in nuclear size and shape. Nonantral endocrine dysplasia in the stomach is seen in the setting of corporal predominant atrophic chronic gastritis and Zollinger-Ellison syndrome with Multiple Endocrine Neoplasia syndrome type I. Condyloma accuminatum is a HPV-related lesion most commonly seen in men practicing anal intercourse. Superimposed squamous dysplasia can be seen with HGD most frequently in the HIV-positive population. Recognition of the different classification systems of dysplasia, the most frequent settings in which these lesions are found, and their natural history is important for all practicing gastroenterologists and pathologists.

Dysplasia in barrett's esophagus. New techniques and markers

In this article, the authors describe the histologic features and classification of dysplasia in Barrett's esophagus. The histologic problems in the diagnosis and grading of dysplasia are discussed. Techniques that can serve as aids to the histologic diagnosis of dysplasia, such as flow cytometry and molecular markers, are reviewed.

Expression of cyclin B1 in the metaplasia-dysplasia-carcinoma sequence of Barrett esophagus

BACKGROUND

It is known that proliferation is deregulated progressively during carcinogenesis in Barrett esophagus (BE). Cyclin B1 is a key protein for the regulation of G2-M-phase transition during the cell cycle and is essential for initiation of mitosis.

METHODS

Using immunohistochemistry, samples of Barrett metaplastic specialized epithelium (SE; n = 36 samples), low-grade dysplasia (LGD; n = 25 samples), high-grade dysplasia (HGD; n = 25 samples), and invasive adenocarcinoma (CA; n = 46 samples) derived from 50 esophagectomy specimens were investigated for the expression of cyclin B1. The number of cyclin B1 positive cells was determined semiquantitatively. In addition, in SE, LGD, and HGD samples, the pattern of cyclin B1 expression was assessed by determination of the presence of positive cells in four mucosal compartments: the deep glandular zone, the lower crypt zone, the upper crypt zone, and the luminal surface.

RESULTS

Cyclin B1 expression was found in all lesions under investigation. Regarding the percentage of positive cells, a marked increase of cyclin B1 positive cells was observed in SE samples compared with LGD samples and in HGD samples compared with CA samples (chi-square test; P < 0.0001), nevertheless showing a broad overlap between the different lesions. Concerning staining patterns, in the majority of SE samples (72.2%), cyclin B1 positive cells were restricted to the glandular zone and the lower crypt zone. In contrast, an expansion of cyclin B1 positive cells to superficially located zones of the mucosa (the upper crypt zone and/or the luminal surface) was observed in the majority of LGD samples (96.0%) and HGD samples (100%; P < 0.0001).

CONCLUSIONS

Overexpression of cyclin B1 is a frequent and early finding in the metaplasia-dysplasia-carcinoma sequence in BE. It may contribute to the loss of growth control and, subsequently, to the development of tumors in this location.

Ki-67 immunoquantitation in cervical intraepithelial neoplasia (CIN): a sensitive marker for grading

The aim of this study was to assess the value of Ki-67 immunoquantitation with a computerized image analysis system for grading support in cervical intraepithelial neoplasia (CIN). Sixty-five 'blind' consensus biopsies (23 CIN 1, 22 CIN 2, and 20 CIN 3) were used as a learning set. Measurements were done in the carefully selected most severely dysplastic part of the epithelium of each CIN case. The resulting discriminating combination of quantitative features was then prospectively applied on 121 new biopsies (test set) and compared with the classical CIN grade assessed routinely by six different pathologists and with the blind review grades assessed by two experienced pathologists. In the learning set of 65 cases, a jack-knifed stepwise discriminant analysis showed that the 90th percentile of the stratification index and the number of positive nuclei per 100 microm basal membrane are the best discriminating set of features to distinguish the three CIN grades at the same time. With these features, two CIN 1 cases were 'misclassified' as CIN 2 and nine CIN 2 cases as CIN 3. Overall agreement, therefore, was only 83%. However, recut of the paraffin blocks in the two 'misclassified' CIN 1 cases revealed CIN 2 in the first and CIN 3 in the other, while the other CIN 1 cases that were correctly classified with Ki-67 quantitation remained CIN 1. Likewise, nine CIN 2 cases were misclassified as CIN 3, but in two of these nine cases histological follow-up clearly indicated CIN 3. Agreement may thus be higher than the 83% in the learning set suggests. In the subsequent prospective evaluation on 121 routine CIN cases (test set), agreement between routine CIN grades (by six independent different pathologists) and quantitative Ki-67 classification was 78%. However, when compared with the blind review CIN grades of two expert pathologists, agreement was 97% and sensitivity, specificity, and positive and negative predictive value were very high. It is concluded that Ki-67 immunoquantitation is a useful diagnostic adjunct to distinguish different CIN grades and may also be a sensitive biological indicator of progression of seemingly low-grade CIN.

Rapid quantitative assessment of gastric corpus atrophy in tissue sections

BACKGROUND/AIMS

Grading of Helicobacter pylori induced atrophic gastritis using the updated Sydney system is severely limited by high interobserver variability. The aim of this study was to set up a quantitative test of gastric corpus mucosal atrophy in tissue sections and test its reproducibility and correlation with the Sydney scores of atrophy.

METHOD

Mucosal atrophy was assessed in 124 haematoxylin and eosin stained corpus biopsy specimens by two experienced gastrointestinal pathologists (EB, JL) according to the updated Sydney system as none (n = 33), mild (n = 33), moderate (n = 33), or pronounced (n = 25). In each specimen, the proportions of glands, stroma, infiltrate, and intestinal metaplasia in the glandular zone were measured as volume percentages using a point counting method. The optimal point sample size, intra-observer and interobserver reproducibility, discriminative power for degrees of atrophy, and correlations with H pylori status were evaluated.

RESULTS

Counting 400 points in 200 fields of vision provided the smallest sample size that still had excellent intra-observer and interobserver reproducibility (r > or = 0.96). Overall, the volume percentage of glands (VPGL), infiltrate (VPI), and stroma (VPS) correlated well with the Sydney scores for atrophy (p < or = 0.003). However, no differences were found between non-atrophic mucosa and mild atrophy. No correlation was found between age and either the Sydney grade of atrophy or the VPGL or VPS. In non-atrophic mucosa and mild atrophy, H pylori positive cases showed a significantly higher VPI than did H pylori negative cases. A lower VPGL was seen in H pylori positive cases than in H pylori negative cases in the mild atrophy group. VPS did not correlate with H pylori status within each grade of atrophy.

CONCLUSION

Point counting is a powerful and reproducible tool for the quantitative analysis of mucosal corpus atrophy in tissue sections. These data favour the combination of "none" and "mild" atrophy into one category, resulting in a three class grading system for corpus atrophy, when using the updated Sydney system.

Computerized quantitative pathology for the grading of dysplasia in surveillance biopsies of Barrett's oesophagus

Decision models for surveillance of Barrett's oesophagus (BO) are governed by the grade of dysplasia on endoscopic biopsy, but subjective grading is prone to observer variation. Computerized morphometry and immunoquantitation can objectively discriminate between different grades of dysplasia in oesophagectomy specimens with BO. The present study evaluated the feasibility of such quantitative analysis on surveillance biopsies of BO. Biopsy criteria for quantitative analysis were defined, excluding 101 (21%) of 472 archival BO surveillance biopsies. In the remaining haematoxylin and eosin (H&E) sections, 105 areas that distinctively displayed no dysplasia (ND), low-grade dysplasia (LGD) or high-grade dysplasia (HGD) were demarcated. Agreement on double-blind examination by two experienced pathologists was reached in 66 areas (63%; kappa: 0.44). For 21 ND/LGD and 11 LGD/HGD disagreement areas, corresponding sections for p53 and Ki67 immunohistochemistry were available. The best combination of two discriminating features was stratification index (SI) with p53 area % for ND versus LGD (89% correct classification), and SI with Ki67 area % for LGD versus HGD (91% correct classification). Fifteen of the 21 ND/LGD disagreement areas could be classified uniquely as either ND or LGD by SI and p53, and eight of the 11 LGD/HGD disagreement areas as either LGD or HGD by SI and Ki67. Correlation coefficients for repeated measurements of SI, Ki67, and p53 by the same observer were 0.94, 0.92, and 0.86, and by two independent observers 0.86, 0.93, and 0.92, respectively. Computerized quantitative pathology on BO surveillance biopsies is feasible provided that well-defined biopsy criteria are used. Using a combination of features associated with cellular differentiation and proliferation, such as SI, p53, and Ki67, quantitative pathological analysis assists in reducing diagnostic variability in the grading of dysplasia during surveillance of BO.

Malignant progression in Barrett's esophagus: pathology and molecular biology

Due to its increasing incidence, esophageal adenocarcinoma and its precursor lesions have received increasing attention in recent years. The histopathologic steps in the process of malignant progression in Barrett's esophagus are well described and include the following: (a) metaplasia of the normal esophageal squamous epithelium to a specialized intestinal glandular epithelium, (b) development of dysplasia (classified histologically as low and high grade), and (c) development of adenocarcinoma characterized by invasive and metastatic potential. Intestinal metaplasia can be identified by the presence of goblet cells, the detection of which can be aided by finding mucin stained by Alcian blue at low pH. Despite this well-characterized sequence, the timing of the development of dysplasia and the subsequent transition to carcinoma and the risk of development of carcinoma in low- and high-grade dysplasia are not precisely known. In addition, there are problems in the identification of dysplasia, including sampling error and interobserver discrepancies among pathologists. A better understanding of the mechanisms of these events would allow early identification and elimination of high-risk lesions before adenocarcinoma with its attendant poor prognosis were able to develop. In order to better understand this process and to potentially identify early markers of malignant transformation, a variety of molecular studies have been carried out in recent years on adenocarcinoma and its precursor lesions in Barrett's esophagus. On the phenotypic level, increased expression and changes in pattern of expression of proliferation marker (Mib-1) Ki-67 antigen, overexpression of p53 protein, overexpression of growth factors such as epidermal growth factor (EGF), c-erbB2, and transforming growth factor (TGF)-a, decreased and abnormal expression of the cell adhesion molecule E-cadherin, and, in carcinomas, increased expression of serine proteases have all been described. A new area of interest is the family of rab proteins, which play an important role in maintaining cell polarity in the gastrointestinal tract. Increased expression of one of these proteins, rab11, has been described in low-grade, but not high-grade dysplasia. In cytogenetic studies, an increased S-phase fraction, followed by an increased tetraploid (4N) fraction and then aneuploidy, has been described. So far, the specific genes which have been most thoroughly investigated have been p53, APC, p16, and the sites of probable tumor suppressor genes, including 3p (FHIT), 13q, and 18q. With only a few exceptions (i.e., rab11 expression, and possibly mutations of FHIT), the numerous molecular abnormalities which have been described occur late in malignant progression, which means that the best marker which presently exists to identify high-risk lesions in Barrett's esophagus is the histologic identification of dysplasia in endoscopic biopsies, especially high-grade dysplasia. We are presently beginning studies using laser microdissection and competitive genomic hybridization (CGH), which could help to identify new chromosomal areas that might contain genes that are crucial in the early phases of malignant progression in Barrett's esophagus. In the future, identification of such early molecular events which predispose to carcinoma development will allow more precise and earlier risk assessment for individual patients, therefore, enabling more effective therapy.

Computerized quantitative pathology for the grading of dysplasia in surveillance biopsies of Barrett's oesophagus

Decision models for surveillance of Barrett's oesophagus (BO) are governed by the grade of dysplasia on endoscopic biopsy, but subjective grading is prone to observer variation. Computerized morphometry and immunoquantitation can objectively discriminate between different grades of dysplasia in oesophagectomy specimens with BO. The present study evaluated the feasibility of such quantitative analysis on surveillance biopsies of BO. Biopsy criteria for quantitative analysis were defined, excluding 101 (21%) of 472 archival BO surveillance biopsies. In the remaining haematoxylin and eosin (H&E) sections, 105 areas that distinctively displayed no dysplasia (ND), low-grade dysplasia (LGD) or high-grade dysplasia (HGD) were demarcated. Agreement on double-blind examination by two experienced pathologists was reached in 66 areas (63%; kappa: 0.44). For 21 ND/LGD and 11 LGD/HGD disagreement areas, corresponding sections for p53 and Ki67 immunohistochemistry were available. The best combination of two discriminating features was stratification index (SI) with p53 area % for ND versus LGD (89% correct classification), and SI with Ki67 area % for LGD versus HGD (91% correct classification). Fifteen of the 21 ND/LGD disagreement areas could be classified uniquely as either ND or LGD by SI and p53, and eight of the 11 LGD/HGD disagreement areas as either LGD or HGD by SI and Ki67. Correlation coefficients for repeated measurements of SI, Ki67, and p53 by the same observer were 0.94, 0.92, and 0.86, and by two independent observers 0.86, 0.93, and 0.92, respectively. Computerized quantitative pathology on BO surveillance biopsies is feasible provided that well-defined biopsy criteria are used. Using a combination of features associated with cellular differentiation and proliferation, such as SI, p53, and Ki67, quantitative pathological analysis assists in reducing diagnostic variability in the grading of dysplasia during surveillance of BO.

Apoptotic and proliferative activity in the neoplastic progression of Barrett's oesophagus: a comparative study

The balance between proliferation and apoptosis within a tissue is important in controlling its overall growth. When either or both are altered, uncontrolled cell proliferation can contribute to cancer. The aim of this study was to investigate apoptosis and proliferation in the progression from Barrett's oesophagus to adenocarcinoma. Fifty-one paraffin sections of Barrett's mucosa with both intestinal and gastric-type Barrett's mucosa, dysplasia, and adenocarcinoma, from 28 patients, were examined for apoptosis using haematoxylin and eosin (H&E)-stained sections counterstained immunohistochemically with CD45 to distinguish leucocytes from apoptotic bodies. Proliferation was detected by immunohistochemistry using the MIB-1 (Ki-67) antibody. There was an increase in proliferation in dysplastic and carcinomatous tissue compared with metaplastic tissue (p=0.0001). In dysplasia, proliferation was distributed throughout the basal-luminal axis, whereas in metaplasia, cell division was compartmentalized to the lower crypt (p<0.001). Conversely, there was a decrease in apoptosis in the upper crypt and luminal surface in dysplasia and adenocarcinoma compared with metaplasia (p<0.0008). There was a significant increase in apoptotic activity in intestinal-type Barrett's mucosa compared with gastric-type. There was a highly significant increase in the glandular proliferation to apoptosis ratio (GPAR) in the progression of metaplasia to dysplasia to adenocarcinoma (p=0.001). The shift in the GPAR in the progression of neoplastic change suggests that it may be a useful and sensitive marker of neoplastic change in Barrett's oesophagus, especially if the assessment of both apoptotic and proliferative activity in the mucosa can be made easier by more sophisticated technical methods.