Prospective evaluation of multilayered epithelium in Barrett's esophagus

OBJECTIVE

We recently identified a distinctive type of multilayered epithelium in two patients with Barrett's esophagus, which shows morphological characteristics of both squamous and columnar epithelium. This study was performed to prospectively evaluate the prevalence of multilayered epithelium in patients with Barrett's esophagus.

METHODS

Mucosal biopsies were obtained from the squamocolumnar junction (Z-line) of 58 patients with endoscopic evidence of esophageal columnar epithelium and from the gastroesophageal junction in 21 patients without endoscopic evidence of esophageal columnar epithelium. Specimens were evaluated for the presence of multilayered epithelium and goblet cells.

RESULTS

Twenty-four of 58 (41%) of the patients with endoscopic evidence of esophageal columnar epithelium had multilayered epithelium compared with only one of 21 patients (5%) in the control group (p = 0.005). Of the 58 patients in the study group, 43 had goblet cell metaplasia and 15 did not (p < 0.001). Only patients with goblet cell metaplasia had multilayered epithelium. Shorter lengths of columnar epithelium were noted in the 24 patients with goblet cells and multilayered epithelium compared with the 19 patients with goblet cells and no multilayered epithelium (p < 0.05).

CONCLUSIONS

Multilayered epithelium is strongly associated with goblet cell metaplasia in patients with endoscopic evidence of esophageal columnar epithelium. These data support the hypothesis that multilayered epithelium may represent a transitional stage in the development of Barrett's esophagus.

p27 expression in inflammatory bowel disease-associated neoplasia. Further evidence of a unique molecular pathogenesis

The cyclin-dependent kinase inhibitor p27 is a negative regulator of the transition from G1 to S phase of the cell cycle, protects against inflammatory injury and promotes epithelial differentiation. Because p27 protein has been shown to be abnormally expressed both in dysplasia associated with Barrett's esophagus and in sporadic colorectal adenomas, we used immunohistochemistry to evaluate p27 expression in inflammatory bowel disease (IBD)-associated dysplasia and carcinomas. Normal, inflamed, and transitional mucosa, sporadic adenomas, and sporadic colonic carcinomas were studied as controls. In normal colonic epithelium p27 expression was restricted to the superficial, terminally differentiated cells. In colitic and inflamed diverticular mucosa p27 was expressed in the base of the crypts in 86 and 70% of cases, respectively. Similarly, in transitional mucosa adjacent to sporadic carcinomas p27 was expressed in the base of the crypts in all cases. Strong p27 expression extended more frequently from the base of the crypts to superficial cells in IBD-associated dysplasia than in sporadic adenomas (P < 0.007). Twenty of 20 (100%) IBD-associated carcinomas showed low p27 expression (<50% nuclei positive) compared to 6 of 20 (30%) stage-matched sporadic colorectal carcinomas (P < 0.001). We conclude (i) aberrant p27 protein expression in inflamed and IBD-associated nondysplastic mucosa is indistinguishable from that found in transitional mucosa adjacent to sporadic carcinomas; (ii) p27 is overexpressed in dysplastic lesions, perhaps as an attempt to counterbalance proliferative stimuli; and (iii) IBD-associated colorectal carcinomas have significantly lower p27 expression, commonly associated with poor prognosis, than stage-matched sporadic colorectal carcinomas. These findings further substantiate the existence of divergent molecular pathogenetic pathways between these types of carcinomas and suggest an intrinsically more aggressive behavior of IBD-associated colon carcinomas compared to sporadic ones.

Cyclin D1 overexpression combined with N-nitrosomethylbenzylamine increases dysplasia and cellular proliferation in murine esophageal squamous epithelium

We previously described the oral-esophageal tissue-specific expression of cyclin D1 with the Epstein-Barr virus ED-L2 promoter in transgenic mice, and resulting dysplasia. Given the evidence for an interplay between environmental and genetic factors in esophageal squamous carcinogenesis, the aim of this study was to determine the potential cooperation of the nitrosamine compound N-nitrosomethylbenzylamine (NMBA), an esophageal specific carcinogen, in the cyclin D1 transgenic mice. NMBA was first demonstrated to induce dysplasia in two strains of inbred mice, C57BL/6 and FVB/N. Subcutaneous NMBA was then administrated to wild type and transgenic mice beginning at 4 weeks of age. Mice were monitored for the duration of the study for general appearance, activity and weight, and were euthanized at 12 and 15 months. Histopathologic analysis revealed increased severity of dysplasia in cyclin D1 mice treated with NMBA compared with treated age-matched wild-type mice and untreated mice. There was also increased proliferating cell nuclear antigen (PCNA) expression in the esophagi of NMBA treated cyclin D1 mice. Taken together, these findings suggest that a genetic alteration, specifically cyclin D1 overexpression and a chemical carinogen, NMBA, may cooperate to increase the severity of esophageal squamous dysplasia, a prominent precursor to carcinoma.

A transgenic mouse model with cyclin D1 overexpression results in cell cycle, epidermal growth factor receptor, and p53 abnormalities

The cyclin D1 oncogene is critical in the progression of the cell cycle through the G1 phase. It is frequently overexpressed in squamous cell carcinomas originating from the head/neck and esophagus. Yet, the functional consequences of aberrant cyclin D1 overexpression are not entirely understood apart from increased cell proliferation. To address this question, we have developed a transgenic mouse model in which the EBV ED-L2 promoter targets cyclin D1 to the stratified squamous epithelium in a tissue-specific fashion to the tongue and esophagus, thereby resulting in a dysplastic phenotype. We now demonstrate that the dysplastic phenotype is associated with increased cell proliferation based on proliferating cell nuclear antigen overexpression and abnormalities in cyclin-dependent kinase 4, epidermal growth factor receptor, and p53. In aggregate, these studies suggest that alterations in certain oncogenes and tumor suppressor genes occur early during head/neck and esophageal carcinogenesis.

The targeting of the cyclin D1 oncogene by an Epstein-Barr virus promoter in transgenic mice causes dysplasia in the tongue, esophagus and forestomach

Cyclin D1 in cooperation with its major catalytic partners, cyclin-dependent kinases cdk4 and cdk6, facilitates progression through the G1 phase of the eukaryotic cell cycle, in part through phosphorylation of the retinoblastoma protein. Cyclin D1's oncogenic properties have been suggested by its cooperation with ras or adenovirus E1a to transform cultured cells, as well its overexpression in transgenic mice that leads to breast cancer. Activated by a number of different mechanisms in human cancers, the cyclin D1 gene is frequently amplified in squamous epithelial cancers derived from the head/neck and esophageal regions. In order to study the functional consequences of cyclin D1 overexpression in these squamous epithelial specific sites, we have linked the Epstein-Barr virus ED-L2 promoter to the human cyclin D1 cDNA and utilized this transgene to generate founder lines. This transgene is transcribed specifically in the tongue, esophagus and forestomach, all sharing a stratified squamous epithelium. The transgene protein product localizes to the basal and suprabasal compartments of these squamous epithelial tissues, and mice from different lines develop dysplasia, a prominent precursor to carcinoma, by 16 months of age in contrast to age-matched wild-type mice. This transgenic model is useful in demonstrating cyclin D1 may be a tumor initiating event in aero-upper digestive squamous epithelial tissues.

Gastric and esophageal intraepithelial lymphocytes in pediatric celiac disease

Celiac disease (CD) is associated with marked mononuclear cell inflammation in the small intestinal mucosa. This study was performed to evaluate analogous changes in the gastric and esophageal mucosa of pediatric patients with CD, with emphasis on epithelial lymphocytosis. We evaluated intraepithelial lymphocytes (IELs) in 23 gastric (no.IELs/100 epithelial cells) and 14 esophageal mucosal biopsy specimens (IELs/hpf) from 23 pediatric cases of CD and 10 nonceliac matched controls. Four patients had postgluten withdrawal biopsy specimens reviewed, and one of these had further postgluten challenge biopsy specimens evaluated as well. Gastric specimens from the CD cases showed a significantly increased IEL count (20.5 +/- 14.4; range, 4-50) compared to controls (3.4 +/- 1.9; range, 1-8; p < 0.001), which also correlated directly with the histologic severity of the small intestinal disease as assessed by the degree of villous shortening. Sixteen (69.5%) of 23 gastric specimens showed > 8 IELs, which was the highest value obtained in control specimens. The four posttreatment specimens showed a significant reduction in the gastric IEL counts from a mean of 19.8 to 3.5 IELs/100 epithelial cells (p < 0.001). The single case that had a further postgluten challenge biopsy showed a return to the pregluten withdrawal IEL count. However, the degree of gastric intraepithelial lymphocytosis did not correlate with any of the clinical data, such as age, gender, presenting symptoms, or serum antibody levels (antigliadin, antireticulin, or antiendomysium). Furthermore, no differences were observed in the IEL count in CD esophageal specimens (5.3 +/- 2.6; range, 2-10) compared to controls (5.2 +/- 1.5; range, 3-8; p = 0.935). These findings suggest that an immune-mediated lymphocytic response linked to gluten occurs in the gastric epithelium, similar to that seen in the small intestine of pediatric patients with CD. Therefore, gastric intraepithelial lymphocytosis may represent a concurrent manifestation of CD rather than a separate entity in the pediatric population.

Barrett's esophagus: metaplastic cells with loss of heterozygosity at the APC gene locus are clonal precursors to invasive adenocarcinoma

Adenocarcinoma in Barrett's esophagus is the second most rapidly increasing cancer in western society. The cause and pathogenesis are unknown. Although histological studies suggest that there is successive progression from metaplasia and dysplasia, with a high risk of subsequent invasive carcinoma, at present there is no direct evidence that metaplastic and dysplastic epithelia are clonal precursors of adenocarcinoma. We selected 12 esophagectomy specimens of Barrett's esophagus patients, which showed a spectrum of normal tissue, metaplasia, dysplasia, and invasive carcinoma in each individual biopsy. We applied the microdissection technique to selectively procure microscopic tissue samples from H&E-stained slides for genetic evaluation using polymorphic markers flanking the APC gene locus. Identical APC gene alterations were found in the dysplastic and adenocarcinoma foci of all informative cases. The same changes were observed even in some metaplastic foci adjacent to dysplasia. Furthermore, clonality analysis of X-chromosome inactivation in female cases verified the same X-chromosome inactivation pattern in carcinoma, dysplasia, and metaplasia adjacent to dysplasia. No APC gene alterations were found in the normal epithelium and metaplasia distant from dysplasia. These data show for the first time that a tissue field of genotypic changes precedes the histopathological phenotypic changes of carcinoma in Barrett's esophagus syndrome. Our findings, in conjunction with the applied tissue microdissection technique, may help identify genotypic changes in patients with Barrett's esophagus before phenotypic changes occur. Therefore, genotyping of Barrett's metaplastic epithelium may supplement the histopathological evaluation of Barrett's esophagus.

Hypertrophic gastropathy in Helicobacter felis-infected wild-type C57BL/6 mice and p53 hemizygous transgenic mice

BACKGROUND & AIMS

Helicobacter pylori infection causes gastritis and peptic ulcers and is linked epidemiologically to gastric cancer. To analyze host genetic factors and the influence of Helicobacter on cell proliferation, we used an inbred and p53 hemizygous mouse model of Helicobacter felis-induced gastritis.

METHODS

H. felis was inoculated by gastric intubation into SPF C57BL/6 wild-type and p53 hemizygous mice that were followed up for 1 year and compared with uninfected controls of the same genotype using histology, proliferating cell nuclear antigen (PCNA) staining, and 5-bromo-2'-deoxyuridine (BrdU) analysis.

RESULTS

Infected animalls developed sustained anti-H. felis serum immunoglobulin G antibody responses. Six months after infection, both wild-type and p53 hemizygous mice showed active chronic inflammation and marked mucosal hyperplasia compared with uninfected controls. One year after infection with H. felis, the wild-type and p53 hemizygous mice showed severe adenomatous and cystic hyperplasia of the surface foveolar epithelium. BrdU uptake and PCNA staining were markedly increased in both sets of infected mice compared with controls. Infected p53 hemizygous mice had a higher proliferative index than the infected wild-type mice.

CONCLUSIONS

H. felis can induce a hypertrophic gastropathy in the C57BL/6 genotype; loss of one p53 allele, although insufficient to initiate carcinogenesis at 1 year, enhances the proliferative index, which may lead to an increased risk of cancer induction.

Duodenal adenomas in familial adenomatous polyposis: relation of cell differentiation and mucin histochemical features to growth pattern

We performed a clinicopathologic analysis of 74 periampullary and duodenal adenomas from 30 patients with familial adenomatous polyposis to evaluate the growth pattern, mucin histochemical profile, and degree and significance of Paneth cell and endocrine cell differentiation in these lesions. A trend toward more numerous adenomas was seen in patients with the longest intervals since their previous colectomies. Adenomas were most often clustered in the periampullary region and were numerous (> 20) in 40% of patients. Periampullary and duodenal adenomas were morphologically similar; both exhibited the same size-villous shape-dysplasia relationship as sporadic and familial adenomatous polyposis-associated colonic adenomas. Adenomas showed a heterogenous pattern of mucin production (mixed small intestinal-large intestinal types), with a shift toward the colonic type (sulfomucin) in lesions that were larger, villous, or severely dysplastic. Ninety-two percent of adenomas showed Paneth cell differentiation (average n Paneth cells/high power field = 24.5), and 99% showed endocrine cell differentiation (average n endocrine cells/high power field = 64.4). In general, the proportion of these specialized cell types was inversely related to size, villous shape, and degree of epithelial dysplasia. These results suggest that periampullary and duodenal adenomas in familial adenomatous polyposis arise from the neoplastic transformation of an undifferentiated stem cell that retains its ability for multidirectional differentiation.

Effect of topical 5-aminosalicylic acid (5-ASA) therapy on rectal mucosal biopsy morphology in chronic ulcerative colitis

Classic teaching emphasizes that chronic ulcerative colitis is characterized morphologically by the presence of fixed architectural and cellular mucosal changes that categorize the process as chronic. To examine the effect of topical 5-aminosalicylic acid (5-ASA) enemas on the presence of six histological features of chronicity in established chronic ulcerative colitis, 123 mucosal biopsies were taken prospectively at 1-month intervals, all from the same anatomic location (10 cm), from 14 patients treated with either 5-ASA or placebo enemas. The biopsies were evaluated for the presence of mixed inflammation in the lamina propria, crypt architectural abnormalities, basally located lymphoid aggregates, basal plasmacytosis, villiform surface epithelial configuration, and Paneth cell metaplasia. Overall, 29% of biopsies from 64% of patients were histologically normal (no chronic features, no active disease). Compared with patients treated with placebo enemas, patients treated with 5-ASA enemas showed a significantly higher percentage of normal biopsies (36% ASA group vs. 12% placebo group; p = 0.005) and a lower percentage occurrence of each individual histological feature of chronicity. In addition, patients treated with 5-ASA had a higher average number of normal biopsies per patient (3.0) than those treated with placebo enemas (1.3). Therefore, histologically normal-appearing mucosal biopsies do occur in established cases of chronic ulcerative colitis, and this finding is enhanced by treatment with 5-ASA enemas. Awareness of these results should prevent the presence of normal rectal mucosal biopsy findings in chronic ulcerative colitis patients from being misinterpreted as either evidence against this diagnosis or as representing focal skip areas characteristic of Crohn's disease.

Esophageal squamous papillomas. A clinicopathologic study of 38 lesions and analysis for human papillomavirus by the polymerase chain reaction

The pathogenesis of esophageal squamous papilloma is not known, but chronic mucosal irritation and infection with human papillomavirus are two proposed etiologies. To investigate these hypotheses, we analyzed the clinical data and histological features of 38 esophageal squamous papillomas from 33 patients and performed the polymerase chain reaction technique for detection of several common human papilloma virus types on a subset of cases (n = 26) with sufficient available material. Clinically, males were affected more often than females (M:F ratio = 24:9); average age was 50 (range, 2-86 years). Most papillomas occurred singly (85%) and were located in the distal esophagus (70%). Patients with esophageal squamous papillomas, especially those with lesions in the distal esophagus, commonly had an associated chronic and often severe form of esophageal mucosal irritation such as esophagitis or Barrett's esophagus. Esophageal squamous papillomas were small polyps (average size, 0.5 cm) that we classified histologically into three types (exophytic, 50%; endophytic, 37%; spiked, 13%) based on the predominant shape of the squamous papillae. Fifty percent of the papillomas (13 of 26) tested, from 57% of patients (12 of 21), were positive for human papilloma virus, most commonly type 16 (nine of 13), less often type 16 and 18 together (3/13), and rarely type 6b/11 (1 of 13). We propose a multifactorial etiology in which the synergistic action of mucosal irritation and human papilloma virus may be necessary for the development of esophageal squamous papillomas.

Compartmental analysis of the pharmacokinetics of radioiodinated monoclonal antibody B72.3 in colon cancer patients

Sixteen patients with colorectal cancer were administered 37-74 MBq (1 mg) of radioiodinated B72.3 monoclonal antibody. Pharmacokinetic analysis was carried out on plasma and urine samples. Elimination from the plasma was biexponential with a mean T1/2 alpha of 3.7 h and T1/2 beta of 62.4 h. The plasma clearance was fit to a two-compartmental model. This was combined with a previously reported model for radioiodine to construct a composite model. There was a good correlation (r = 0.952) between the model-predicted and observed excretion of radioiodine suggesting that the composite model is compatible with the pharmacokinetics of the radiolabelled antibody.

Malignant paraganglioma of the posterior mediastinum. A case report and review of the literature

A case of malignant paraganglioma arising from the posterior mediastinum and presenting with a chest wall metastasis is reported with immunocytochemical and ultrastructural documentation. The pathobiologic features of this rare disease are reassessed with a review of the literature. Cytoarchitectural features do not provide reliable information regarding malignant potential. However, evidence of local invasiveness at surgical exploration and/or lack of initial surgical control are likely to be associated with synchronous or metachronous metastatic disease. Although there are clinicopathologic differences warranting distinction between benign paragangliomas arising in the anterior and posterior mediastinal compartments, there is no apparent pathobiologic difference with regard to the malignant group.

Tubular adenomatous metaplasia (nephrogenic adenoma) of the female urethra

We present a case of tubular adenomatous metaplasia (nephrogenic adenoma) arising within a urethral diverticulum in a woman complaining of a vaginal mass with dyspareunia. This lesion, which uncommonly affects the urethra, may clinically manifest as a gynecologic condition and mimic a low-grade adenocarcinoma on pathologic assessment. Criteria for diagnosis and current concepts of pathogenesis are discussed. Our findings, including an immunocytochemical work-up, support the concept of a reactive metaplastic response rather than nephrogenic differentiation.

Enhanced carcinogenesis in the proximal small intestine of the rat following rumenectomy

Various techniques have been used to enhance carcinogenesis in experimental animals. This study examines the effects of the excision of the forestomach (rumen), a squamous epithelial pouch of the rat, on the incidence and distribution of intestinal neoplasms induced by 1,2-dimethylhydrazine (DMH). Thirty-four male Sprague-Dawley rats were randomly assigned to control and experimental groups. The experimental group was subjected to an excision of the rumen while the control group underwent a gastro-rumenotomy and closure. Following a two week recovery period, each animal was weighed and injected with DMH (20 mgm/kg body wt) on a weekly basis for 22 weeks. At 24 weeks, the 32 surviving rats were sacrificed and the number, location, and histology of the neoplasms in the intestinal tract of each rat were noted. Rumenectomy resulted in a statistically increased incidence of neoplasms in the proximal small bowel (mean of 1.3 +/- 0.01 neoplasms/rat) when compared with the control group (mean of 0.1 +/- 0.2 neoplasms/rat) (p less than 0.001); but did not influence the incidence, distribution, or histology of colonic neoplasms between control and experimental animals. All neoplasms of the proximal small bowel when examined histologically were classified as invasive adenocarcinomas. The colon contained adenomata and carcinoma in situ, as well as adenocarcinomas. It is therefore concluded that excision of the rumen of the rat stomach selectively promotes malignant formation in the proximal small bowel following repeated injections of DMH.