Karyometric image analysis for intraepithelial and invasive cervical lesions

OBJECTIVE: To derive an objective, numeric measure for the progression of intraepithelial and invasive squamous cell cervical lesions. STUDY DESIGN: Thin-layer cervical cytology preparations from colposcopically confirmed normal cervix, low grade squamous intraepithelial lesions, high grade squamous intraepithelial lesions and carcinoma were identified from a cross-sectional study. Fifty-nine cases representing 4 diagnostic categories were selected, and 2,375 nuclei from epithelial cells representative of the diagnostic category were randomly selected for imaging and measurement from these cases. Additionally, 1,378 visually normal appearing intermediate cells from low and high grade squamous intraepithelial lesions, as well as from carcinoma cases, were identified for analysis. The nuclei were quantitatively characterized, and discriminant analyses were performed to derive a progression curve from normal cytology to carcinoma. RESULTS: The lesion signatures show a clear increase in nuclear abnormality with increasing progression. A progression curve was derived based on mean discriminant function scores for each diagnostic category and on the mean nuclear abnormality values for the nuclei in each category, as expressed by their deviation in feature values from normal reference nuclei. CONCLUSION: A numeric assessment of lesion progression for cervical precancerous and cancerous lesions based on karyometric measurements is possible and may provide an objective, precise characterization of each lesion as well as a basis for improved performance in automated cytology-based cervical cancer screening.     

Progression curves for endometrial lesions

OBJECTIVE: To derive a numeric measure for the progression of endometrial lesions as a baseline study for an eventual assessment of chemopreventive intervention efficacy. STUDY DESIGN: Tissue sections from normal endometrium at the proliferative and secretory phase, simple hyperplasia, atypical hyperplasia from cases free of concomitant adenocarcinoma and adenocarcinoma of the endometrium were recorded at high spatial resolution. Six cases from each diagnostic category were chosen as "typical," and 60 epithelial nuclei were randomly selected for measurement for each case. Discriminant analyses were carried out to derive a direction of progressive change in feature space and to correct the progression curve for the presence of cells not expressing progressive change among the random sample of nuclei. RESULTS: A well-conditioned progression curve was derived based on the mean discriminant function scores for each diagnostic category and the mean nuclear abnormality of the nuclei in each category, as expressed by their deviation in feature values from normal reference nuclei. The lesion signatures showed a clear trend toward extension into the range of higher nuclear abnormalities with increasing progression. There was an indication that abnormal endometrial lesions may comprise cases with distinctly different degrees of nuclear abnormality. CONCLUSION: A numeric assessment of lesion progression for endometrial lesions, based on karyometric measurements, is possible. The data suggest that additional analysis may provide further characterizing information for individual lesions.     

Nuclear chromatin characteristics of breast solid pattern ductal carcinoma in situ.

OBJECTIVE: To characterize nuclei from breast solid pattern ductal carcinoma in situ (DCIS) by their karyometric features and to search for the presence of statistically significantly different subsets of nuclei. STUDY DESIGN: One hundred nuclei from each of 6 normal, 13 solid DCIS, (9 low and intermediate grade and 4 high grade DCIS) histopathologic samples of breast tissue were digitally recorded. Karyometric features were computed and subjected to a nonsupervised learning algorithm (P-index) to identify significantly different subgroups. RESULTS: Nuclei in low grade lesions displayed a diploid/near diploid pattern, while the majority of intermediate grade lesions fell into a range beyond 5N. The high grade lesions showed substantial genomic instability and represented three statistically different subsets or phenotypes. CONCLUSION: There is a progression of nuclear abnormality from low grade to high grade DCIS. The nuclei from high grade DCIS form a heterogeneous set that represents three phenotypes. One of these phenotypes shows a nuclear chromatin pattern that more closely resembles poorly differentiated, infiltrating disease. The observation of such a phenotype may have prognostic implications.     

Molecular imaging using fluorescent lectins permits rapid endoscopic identification of dysplasia in Barrett's esophagus

Barrett's esophagus is an example of a pre-invasive state, for which current endoscopic surveillance methods to detect dysplasia are time consuming and inadequate. The prognosis of cancer arising in Barrett's esophagus is improved by early detection at the stage of mucosal carcinoma or high-grade dysplasia. Molecular imaging methods could revolutionize the detection of dysplasia, provided they permit a wide field of view and highlight abnormalities in real time. We show here that cell-surface glycans are altered in the progression from Barrett's esophagus to adenocarcinoma and lead to specific changes in lectin binding patterns. We chose wheat germ agglutinin as a candidate lectin with clinical potential. The binding of wheat germ agglutinin to human tissue was determined to be specific, and we validated this specific binding by successful endoscopic visualization of high-grade dysplastic lesions, which were not detectable by conventional endoscopy, with a high signal-to-background ratio of over 5.     

Association of metallothionein expression and lack of apoptosis with progression of carcinogenesis in Barrett's esophagus

Barrett's esophagus is the transformation of normal esophageal squamous epithelium to specialized intestinal metaplasia (SIM). Among the Barrett's specialized cells, those that can develop protective mechanisms against apoptosis may have potential to become malignant. Studies have shown that overexpression of metallothionein (MT), low molecular protein that protects cells from apoptotic stimuli, appears to be associated with more advanced, highly malignant tumors. We thus investigated the relationship between MT expression and apoptosis in different stages of Barrett's carcinogenesis. Terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling and immunohistochemical dual-staining assay were performed in human biopsy samples of normal, SIM, dysplasia, and adenocarcinoma. Apoptotic index and MT expression were quantified by using an image system to analyze the converted digital data. A negative correlation between MT expression and apoptotic index was found. MT expression was significantly increased along with the histologic progression towards adenocarcinoma. This study thus suggests that MT may contribute to cytoprotection, thereby inhibiting apoptosis and leading to carcinogenesis of Barrett's esophageal cells.     

Chromatin texture in high grade prostatic intraepithelial neoplasia and early invasive carcinoma

OBJECTIVE: To evaluate individual nuclei from high grade prostatic intraepithelial neoplasia (PIN) lesions with early invasive carcinoma foci in the area of microinvasion and in the gland in which the microinvasion originated. STUDY DESIGN: High-resolution, digitized images of nuclei from defined locations were recorded and segmented, and karyometric variables were computed. These included a set of 93 features, which form a nuclear signature characterizing the spatial and statistical distribution of the nuclear chromatin. Nuclei in the glandular epithelium were recorded sequentially, along the basal cell layer, at increasing distances from the point of microinvasion and by random selection in the region of microinvasion. RESULTS: At a distance > 60 nuclear locations from the point of microinvasion, the nuclear signatures corresponded to those seen in high grade PIN. Between 40 and 20 nuclear locations removed from the microinvasion focus the signatures began to change gradually until at a distance of 15-5 locations they strongly resembled the signatures seen in adenocarcinoma. The total optical density decreased to values seen in adenocarcinoma, and the nuclear chromatin had finer granularity. While nuclei in high grade PIN followed a widely dispersed total optical density distribution suggestive of wide-ranging aneuploidy, the nuclei in the region of microinvasion exhibited a less dispersed and bimodal total optical density distribution. CONCLUSION: The chromatin texture signatures showed a clear trend: there was an obvious attenuation as the measured nuclei approached the microinvasion area. The decrease in total optical density at the microinvasion might suggest the emergence of one or two clones that can be responsible for the invasive phenotype.     

Deoxycholic acid impairs glycosylation and fucosylation processes in esophageal epithelial cells

It is generally accepted that esophageal adenocarcinoma arises from a Barrett's metaplastic lesion. Altered glycoprotein expression has been demonstrated in tissue from patients with Barrett's esophagus and esophageal cancer but the mechanisms regarding such changes are unknown. The bile acid deoxycholic acid (DCA) alters many cell signaling pathways and is implicated in esophageal cancer progression. We have demonstrated that DCA disrupts Golgi structure and affects protein secretion and glycosylation processes in cell lines derived from normal squamous epithelium (HET-1A) and Barrett's metaplastic epithelium (QH). Cell surface expression of glycans was identified using carbohydrate-specific probes (wheat germ agglutinate, conconavalin A, peanut agglutinin, lithocholic acid and Ulex europaeus agglutinin) that monitored N-glycosylation, O-glycosylation and core fucosylation in resting and DCA-treated cells. DCA altered intracellular localization and reduced cell surface expression of N-acetyl-D-glucosamine, α-methyl-mannopyranoside (Man/Glc) and fucose in both cell lines. Furthermore, DCA reduced the expression of epithelial growth factor receptor and E-cadherin in a manner analogous to treatment of cells with the N-glycan biosynthesis inhibitor tunicamycin. This is the first study to identify an altered Golgi structure and glycomic profile in response to DCA in esophageal epithelial cells, a process which could potentially contribute to metaplasia, dysplasia and cancer of the esophagus.     

Cytologic features of premalignant glandular lesions in the upper gastrointestinal tract

The cytologic findings in 13 endoscopic brushing specimens from biopsy-proven premalignant glandular lesions (PGLs) of the upper gastrointestinal tract were reviewed retrospectively. The specimens were from ten patients: three with dysplasia in Barrett's esophagus, four with gastric adenomas and three with duodenal adenomas. One dysplasia in Barrett's esophagus and four adenomas (two gastric and two duodenal) had coexisting adenocarcinomas. Most pure PGLs were characterized cytologically by cohesive three-dimensional clusters of cells with more-or-less uniformly enlarged nuclei and an increased nuclear/cytoplasmic ratio. Crowding and molding were present within these clusters; however, the cells were arranged in a somewhat orderly or palisading fashion, instead of entirely haphazardly. In cases of carcinoma coexisting with adenoma or dysplasia, the atypical cells tended to be more pleomorphic and dyshesive. In one specimen from an adenocarcinoma arising in an adenoma, the adenomatous and carcinomatous components could be distinguished cytologically.     

DNA methylation profiling in Barrett's esophagus and esophageal adenocarcinoma reveals unique methylation signatures and molecular subclasses

Barrett's esophagus (BE) is a metaplastic process whereby the normal stratified, squamous esophageal epithelium is replaced by specialized intestinal epithelium. Barrett's is the only accepted precursor lesion for esophageal adenocarcinoma (EAC), a solid tumor that is rapidly increasing in incidence in western countries. BE evolves into EAC through intermediate steps that involve increasing degrees of dysplasia. Current histologic criteria are quite subjective and the clinical behavior of BE is highly variable and difficult to predict using these standards. It is widely believed that molecular alterations present in BE and EAC will provide more precise prognostic and predictive markers for these conditions than the current clinical and histologic features in use. In order to further define molecular alterations that can classify unique groups of BE and EAC, we utilized methylation microarrays to compare the global gene methylation status of a collection of normal squamous, BE, BE + high-grade dysplasia (HGD), and EAC cases. We found distinct global methylation signatures, as well as differential methylation of specific genes, that discriminated these histological groups. We also noted high and low methylation epigenotypes among the BE and EAC cases. Additional validation of those CpG sites that distinguished BE from BE + HGD and EAC may lead to the discovery of useful biomarkers with potential clinical applications in the diagnosis and prognosis of BE and EAC.     

p53 and the malignant progression of Barrett's esophagus

Barrett's esophagus (BE) is a metaplastic disorder in which specialized columnar epithelium replaces healthy squamous epithelium (intestinal metaplasia). Even though its pathophysiology and the steps of its neoplastic progression are not completely understood, BE can be considered as a complication of gastroesophageal reflux disease (GERD). Given that esophageal adenocarcinoma, which is continually increasing in the Western world, still has a poor prognosis and suffers from late diagnosis, and because BE is a precancerous lesion, there is a strong need for good molecular markers of malignant progression in Barrett's metaplasia (BM). The aim of this review is to examine the published data regarding the role that assessment of p53 may play in the management of BE, trying to understand if it may be a useful marker to early diagnose BE malignant transformation.     

Karyometry of infiltrating breast lesions

OBJECTIVE: To characterize nuclei from well-differentiated, moderately differentiated and poorly differentiated lesions of invasive breast cancer by karyometry and to test the hypothesis that these diagnostic categories form homogeneous sets. STUDY DESIGN: Histopathologic sections from 6 cases of well-differentiated, 11 cases of moderately differentiated and 17 cases of poorly differentiated ductal carcinomas were digitally recorded. From each case 100 nuclei were segmented and analyzed by karyometry. A discriminant analysis was performed, and nuclear and lesion signatures were computed. The nonsupervised learning algorithm P-index was applied. A progression curve per diagnostic category based on mean nuclear abnormality and a discriminant function score was derived. RESULTS: The well-differentiated lesions formed a homogeneous set, but both the moderately and poorly differentiated lesions showed 2 significantly different subpopulations with nuclei of substantially different nuclear abnormality and progression. CONCLUSION: The visual histopathologic diagnostic assessment of these lesions was based on an evaluation of both tissue architectural criteria and nuclear criteria. Here, only the pattern of nuclear chromatin was evaluated. Cases belonging to the same diagnostic category as assessed by their differentiation may be further characterized by the extent to which the nuclei deviate from normal. There was substantial case-to-case heterogeneity in these invasive lesions.     

Endoscopic screening and surveillance for Barrett's esophagus--clinical implications

There is now a clear causal relationship between symptomatic gastroesophageal reflux and esophageal adenocarcinoma (Lagergren et al, 1999). The risk factor is now identified as Barrett's metaplasia (Solaymani et al, 2004). Chronic reflux results in Barrett's metaplastic change, and the route to carcinoma is a stepwise progression, through dysplasia to invasive carcinoma (Jankowski et al, 2000). Earlier-stage disease is found in patients undergoing surveillance and is the major predictor of survival following surgery (Fountoulakis et al, 2004). Screening and surveillance by endoscopic biopsy regimen has profound implications for the allocation of healthcare resources and the provision of clinical services. Screening a high-risk group such as men with gastroesophageal reflux disease (GERD) will result in the detection of more patients with Barrett's esophagus, many of whom are asymptomatic. Once detected, questions remain as to surveillance intervals and the current methodology for surveillance. There are profound challenges with the accurate endoscopic and pathologic detection and categorization of Barrett's metaplasia, dysplasia , and, indeed, cancer. New endoscopic detection methods are being investigated to improve the diagnosis and definition of the premalignant phenotype. The detection of dysplasia requires increased surveillance and usually intervention either endoscopically or with surgery.     

Karyometry in endometrial adenocarcinoma of different grades

OBJECTIVE: To characterize nuclei from adenocarcinoma of the endometrium of different grades in order to establish whether significantly different nuclear subpopulations exist. STUDY DESIGN: A total of 1,400 nuclei from 14 cases of adenocarcinoma of the endometrium of grades 1, 2 and 3 were recorded, and 600 nucleifrom normal, secretory phase glandular endometrial epithelium were used as a reference data set. Karyometric features were computed and a discriminant function derived to define a trend in feature values for nuclei from lesions of different grades. The nuclei from lesions of different grades were processed by a nonsupervised learning algorithm in an effort to detect and define subpopulations. RESULTS: Nuclei from grade 1 lesions represented a near-diploid stemline, whereas nuclei from grade 3 lesions formed an aneuploid set with a mode around 3N. The existence of three subpopulations with statistically different nuclear chromatin patterns could be shown for nuclei from each grade. In each grade these three subpopulations occupied the same relative position in feature space. For grade 1 lesions all three subpopulations were near diploid, for grade 3 lesions all three were approximately triploid. CONCLUSION: The nuclei in adenocarcinoma of the endometrium form a heterogeneous set, with subpopulations of distinctly different chromatin patterns and different ploidy. This should be taken into consideration in assessing the efficacy of chemopreventive intervention.     

A karyometric approach to the characterization of atypical endometrial hyperplasia with and without co-occurring adenocarcinoma

OBJECTIVE: To develop a karyometric image analysis approach to distinguishing atypical endometrial hyperplasia with and without co-occurring adenocarcinoma. STUDY DESIGN: Six cases of atypical hyperplasia without and 6 cases with co-occurring adenocarcinoma, 4 cases of normal endometrium and 3 cases of adenocarcinoma were identified. From each case 100 nuclei were measured in representative diagnostic areas identified by an experienced pathologist. Discriminant analyses were performed. An unsupervised learning algorithm was applied to define and characterize different nuclear phenotypes, and those data were used to identify cases with co-occurring adenocarcinoma. RESULTS: Discriminant analysis showed that nuclei from atypical hyperplasia and atypical hyperplasia with co-occurring adenocarcinoma are statistically different. The unsupervised learning algorithm revealed differences in nuclear subpopulations that can be used to correctly identify an estimated 85% of individual cases. CONCLUSION: Nuclei from atypical hyperplasia without and with co-occurring adenocarcinoma have statistically different karyometric characteristics that may facilitate case classification.