Adjacent Squamous Epithelium Research Articles

A human Barrett's esophagus organoid system reveals epithelial-mesenchymal plasticity induced by acid and bile salts.

The pathogenesis of subsquamous intestinal metaplasia (SSIM), in which glands of Barrett's esophagus (BE) are buried under esophageal squamous epithelium, is unknown. In a rat model of reflux esophagitis, we found that columnar-lined esophagus developed via a wound-healing process involving epithelial-mesenchymal plasticity (EMP) that buried glands under ulcerated squamous epithelium. To explore a role for reflux-induced EMP in BE, we established and characterized human Barrett's organoids and sought evidence of EMP after treatment with acidic bile salts (AB). We optimized media to grow human BE organoids from immortalized human Barrett's cells and from BE biopsies from seven patients, and we characterized histological, morphological, and molecular features of organoid development. Features and markers of EMP were explored following organoid exposure to AB, with and without a collagen I (COL1) matrix to simulate a wound-healing environment. All media successfully initiated organoid growth, but advanced DMEM/F12 (aDMEM) was best at sustaining organoid viability. Using aDMEM, organoids comprising nongoblet and goblet columnar cells that expressed gastric and intestinal cell markers were generated from BE biopsies of all seven patients. After AB treatment, early-stage Barrett's organoids exhibited EMP with loss of membranous E-cadherin and increased protrusive cell migration, events significantly enhanced by COL1. Using human BE biopsies, we have established Barrett's organoids that recapitulate key histological and molecular features of BE to serve as high-fidelity BE models. Our findings suggest that reflux can induce EMP in human BE, potentially enabling Barrett's cells to migrate under adjacent squamous epithelium to form SSIM.NEW & NOTEWORTHY Using Barrett's esophagus (BE) biopsies, we established organoids recapitulating key BE features. During early stages of organoid development, a GERD-like wound environment-induced features of epithelial-mesenchymal plasticity (EMP) in Barrett's progenitor cells, suggesting that reflux-induced EMP can enable Barrett's cells to migrate underneath squamous epithelium to form subsquamous intestinal metaplasia, a condition that may underlie Barrett's cancers that escape detection by endoscopic surveillance, and recurrences of Barrett's metaplasia following endoscopic eradication therapy.

RA10.03: REGENERATING ESOPHAGEAL SQUAMOUS EPITHELIUM FROM SQUAMOUS PROGENITOR CELLS THROUGH BMP2/4 SIGNAL INHIBITION IN MODELS OF BARRETT's ESOPHAGUS: A PROMISING CHEMOPREVENTIVE TREATMENT FOR ESOPHAGEAL ADENOCARCINOMA

Abstract Background Barrett's esophagus is a metaplastic condition in which the esophageal normal squamous mucosa is replaced by metaplastic columnar type of epithelium, which is a the result of chronic duodeno-gastric reflux, which causes an inflammatory response. One way to divert the risk of malignant progression of Barrett's esophagus would be by re-establishing squamous epithelium through inhibiting Barrett cells. In earlier studies the SHH-BMP4 pathway has been identified as one of the critical pathways involved in the generation of columnar metaplasia. BMPs are secreted stromal factors for instance involved in development and homeostasis of columnar epithelia. Therefore targeting BMPs to modulate signaling and inhibit columnar cell growth and proliferation could be an attractive approach for diverting cancer risk of metaplastic columnar epithelia such as Barrett's esophagus. Methods We first set out to study BMP signaling through analysis of RNA sequencing to identify which BMPs are involved in Barrett's esophagus and in three different models we investigated the effects of specific BMP inhibition and neo-squamous regeration. We finally investigated the origin of the neo-squamous cells by lineage tracing in one of our models. Results We found that In a transgenic mouse model, conditional knock out of the BMP inhibitor Noggin increased BMP signaling and development of columnar metaplasia arising from multilayered glands glands at the squamo-columnar junction in the stomach (figure…). We demonstrate that inhibiting BMP2 and 4, drives development of squamous epithelium in these glands. In for its effect of epithelial healing in an cryo-ablation model. Additionally, to perform lineage tracing using K5-cre-Tomato-GFP lineage tracing mice to investigate the site of origin of the neo-squamous epithelium. Method: Cryoablation of the stomach epithelium in wild-type and CK5 lineage tracing mice was performed just distal of the squamo-columnar junction and mice were treated with saline or intraperitoneal injections of the BMP inhibitor for 0, 7, 14 and 21 days. The healing process of the ablated area was investigated by histology and immunohistochemistry (IHC) using a panel of both squamous (CK5 and p63) and columnar markers (Villin, CK19). Results: At 21 days post ablation, we observed that the inhibition of BMP4 promoted the re-generation of neo-sqaumous epithelium in the ablated area, while the control group showed re-generation of normal stomach epithelium. IHC showed that the neo-squamous epithelium was positive for the CK5 and p63 squamous markers. Lineage tracing indicated that the squamous cells originated for multilayered glands at the squamo-columnar junction and from the adjacent squamous epithelium (Figure 1). Conclusion Our results demonstrate that inhibition of BMP2/4 after ablation of columnar epithelium at the squamo-columnar junction, promotes development of neo-squamous epithelium from submucosal multi-layered glands residing at the SCJ and adjacent squamous epithelium, at the same time the regeneration of columnar epithelium is inhibited. These pre-clinical findings can be translated to a clinical setting in order to optimize ablative therapies for treatment of BE patients. Disclosure All authors have declared no conflicts of interest.

Primary malignant melanoma of the gastroesophageal junction with plasmacytoid features and reactivity to cd138: A case report and review

Melanoma of mucosal sites is rare and is extremely rare in esophagus. Melanoma is known for its histological diversity mimicking any other malignancies with poor prognosis. Clinical presentation may be similar to other gastroesophageal junction malignancies with obstructive symptoms/bleeding with pigmented polypoid mass on endoscopy and gross examination. However, metastasis from elsewhere is to be considered in the absence of melanocytosis in the adjacent squamous epithelium. Immunohistochemistry with a panel of markers is necessary in amelanotic lesions, poorly differentiated morphology, and small biopsy specimens. We report a case of melanoma with plasmacytoid features in the gastroesophageal junction diagnosed in a small biopsy with immunohistochemical findings and follow-up esophagogastrectomy.

Abstract 3949: Deep immunophenotyping using flow cytometry of dissociated cells from Barrett's esophagus and matched adjacent squamous epithelium defines distinct phenotypic clusters

Abstract Barrett's esophagus (BE) is defined as metaplasia of the squamous epithelium to a specialized columnar epithelium with risk factors of gastroesophageal reflux and obesity and a predilection for middle-age and older white males. BE progresses through stages of dysplasia (low-grade and high-grade) before developing into esophageal adenocarcinoma. Challenges remain in early detection and predicting which patients may progress to dysplasia. Here we describe a method by which we compare human clinical IRB-approved BE biopsies and adjacent normal squamous epithelium using tissue dissociation and deep immunophenotyping by flow cytometric collection and analysis. A cassette of canonical epithelial or tumor stem cell-associated targets (EpCAM, CD24, CD44, CD49f, Her2/neu, CD133, CD90, CD166, and CD29), immune cell markers (CD3, CD45, CD127, HLA-DR, CD16, CD56, CD4, CD8, CD25, and CD19), as well as targets associated with myeloid derived suppressor cells (CD14, CD15, CD33, CD11b, HLA-DR, CD31 and CD86) were used to discern differences across subjects and between cellular compartments in normal and BE tissue. The Barrett’s samples show a majority population with a characteristic phenotype (EpCAM+CD133lowCD49fhigh) when compared with normal squamous tissue samples (EpCAM-CD133-CD49flow). The samples separate into two discrete groups using hierarchical clustering based on differential surface marker expression of combined epithelial and immune cell markers, but also reveal unexpected, shared phenotypes for some normal and BE samples. Principal component analysis supports this grouping and was used to identify more compelling targets for categorization, such as CD133 and CD49f. The resulting expression and distribution of targets offer a phenotypic fingerprint characterizing both the epithelial cell and immune cell compartment. Besides providing the potential for revealing clinically relevant differences between BE and normal tissue, as well as across subjects, the discovered surface immunophenotypes can be used to target specific subpopulations from dysplastic tissue for further molecular investigation. A deeper understanding of the role of such specific subpopulations should increase the prospects for more complete understanding of BE and its progression. Citation Format: Friedrich G. Hahn, Eileen Snowden, Warren Porter, Mitchell Ferguson, William S. Dillmore, Stephanie S. Yee, Taylor Black, Maureen DeMarshall, Aaron Middlebrook, Smita Ghanekar, Anil Rustgi, Erica L. Carpenter, Rainer Blaesius. Deep immunophenotyping using flow cytometry of dissociated cells from Barrett's esophagus and matched adjacent squamous epithelium defines distinct phenotypic clusters [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3949. doi:10.1158/1538-7445.AM2017-3949

PWE-011 Aberrantly glycosylated muc1 as a potential therapeutic target for Barrett's with high grade dysplasia and primary and metastatic oesophageal adenocarcinoma

IntroductionPatients with Barrett's (BE) associated oesophageal adenocarcinoma (OA), show strong expression of the mucin MUC1, but binding is not specific to dysplasia or cancer. Aberrant glycosylation of MUC1 (AG-MUC1) accompanies...

Su1882 Aberrantly Glycosylated MUC1 as a Potential Therapeutic Target for Barrett's With High Grade Dysplasia and Primary and Metastatic Oesophageal Adenocarcinoma

Introduction Patients with Barrett9s (BE) associated oesophageal adenocarcinoma (OA), show strong expression of the mucin MUC1, but binding is not specific to dysplasia or cancer. Aberrant glycosylation of MUC1 (AG-MUC1) accompanies the development of cancer in most epithelial tumours, exposing peptides hidden on normal cells. Humanised antihuman milk-fat globule-1 (Hu-HMFG1) antibody binds one of these regions. This study assesses expression of AG-MUC1 in the squamous-metaplasia-dysplasia-OA sequence, in OA specimens with infiltrated nodes and in cancer cell lines. Methods 34 paraffin embedded oesophageal tissue specimens were selected from patients with squamous (n=5), non-dysplastic BE (NDBE; n=3), low grade dysplasia (LGD; n=6), high grade dysplasia (HGD; n=9) and OA (n=11). 11 OA resection specimens with clear margins containing tumour and infiltrated nodes were also stained. Slides were immunostained with Hu-HMFG1 antibody and scored by an expert pathologist. Binding of HuHMFG1 to the cancer cell lines SKOV-3 (ovarian), MCF-7 (breast), OE-19, OE33 (oesophageal) and HT-29 (colon) was examined with flow cytometry using a secondary FITC conjugated antibody and analysed with FloJo. Results AG-MUC1 was significantly expressed (>33% positively stained cells) in 22% of HGD and 36% of OA specimens. Non-significant mild staining was seen in NDBE (100%), LGD (33%), HGD (44%) and OA (64%). In 27% of OA and 43% of HGD, adjacent squamous epithelium also stained. In surgically resected OA9s, 45% stained significantly for AG-MUC1 in primary tumour. Of these, 80% stained significantly in related lymph nodes. All OA resection margins were clear of significant staining. On flow cytometry, binding was noted on SKOV-3, MCF-7, OE-19 but not HT-29 or OE-33. Conclusion This pilot study demonstrates AG-MUC1 to be upregulated in the BE metaplasia-dysplasia-OA sequence with significant staining limited to HGD and cancer. Although some squamous staining was noted, this was likely a field effect as no significant staining was noted in OA resection margins. In patients with significantly stained primary tumour, most had significant staining in infiltrated lymph nodes. Finally, with flow cytometry we identified the OA cell line, OE-19 expressed AG-MUC1 in preparation for in vitro studies. AG-MUC1 targeting with the antibody Hu-HMFG1 offers a novel strategy to target HGD and OA, including those patients presenting with metastatic disease. Competing interests None declared.

Fibroblast-derived HB-EGF promotes Cdx2 expression in esophageal squamous cells

The molecular basis of attaining columnar phenotype in Barrett’s esophagus is poorly understood. One hypothesis states that factors locally produced by cells of mesenchymal origin in chronic reflux esophagitis induce metaplastic transformation. This study was performed to elucidate the factors secreted from fibroblasts that cause columnar phenotype in adjacent squamous epithelium. Human fibroblast cells were exposed to acidified medium for 20 min, followed by medium neutralization for 2 h, and then total RNA was hybridized to Sentrix Human-6 Expression BeadChips. Furthermore, esophageal mucosal biopsy specimens from reflux esophagitis patients were examined for HB-EGF expression using immunohistochemistry. In addition, cells from the human esophageal squamous epithelial cell line HET1A were treated with recombinant HB-EGF, and changes in expressions of Cdx2 and columnar markers were analyzed. The gene expression profile revealed significant upregulation of a variety of growth factors and inflammatory chemokines in response to acid exposure. Among them, HB-EGF was upregulated more than 10-fold. Biopsy specimens from reflux esophagitis patients showed a strong expression of HB-EGF in fibroblast cells underlying the damaged epithelium. Furthermore, in vitro stimulation of HET1A cells with HB-EGF increased Cdx2 in dose-dependent manners. Functional analysis of human Cdx2 promoter also revealed its upregulation by HB-EGF stimulation, showing the role of potential responsive elements (AP-1 and NF-κB) for its transcriptional activation. Moreover, the columnar markers cytokeratin 7 and villin were also upregulated by HB-EGF stimulation. HB-EGF induces several genes characteristics of columnar phenotypes of esophageal squamous epithelium in a paracrine manner.

Neosquamous Epithelium Does Not Typically Arise from Barrett's Epithelium

Neosquamous epithelium (NSE) can arise within Barrett's esophagus as a consequence of medical or surgical acid reduction therapy, as well as after endoscopic ablation. Morphologic studies have suggested that NSE can develop from adjacent squamous epithelium, submucosal gland ducts, or multipotent progenitor cell(s) that can give rise to either squamous or Barrett's epithelium, depending on the luminal environment. The cells responsible for Barrett's epithelium self-renewal are frequently mutated during neoplastic progression. If NSE arises from the same cells that self-renew the Barrett's epithelium, the two tissues should be clonally related and share genetic alterations; if NSE does not originate in the self-renewing Barrett's, NSE and Barrett's esophagus should be genetically independent. We isolated islands of NSE and the surrounding Barrett's epithelium from 20 patients by microdissection and evaluated each tissue for genetic alterations in exon 2 of CDKN2A or exons 5 to 9 of the TP53 gene. Nine patients had p16 mutations and 11 had TP53 mutations within the Barrett's epithelium. In 1 of 20 patients, a focus of NSE had a 146 bp deletion in p16 identical to that found in surrounding Barrett's epithelium. The NSE in the remaining 19 patients was wild-type for p16 or TP53. Our mutational data support the hypothesis that, in most circumstances, NSE originates in cells different from those responsible for self-renewal of Barrett's epithelium. However, in one case, NSE and Barrett's epithelium seem to have arisen from a progenitor cell that was capable of differentiating into either intestinal metaplasia or NSE.

Activated nuclear factor-kappa B and cytokine profiles in the esophagus parallel tumor regression following neoadjuvant chemoradiotherapy

Esophageal adenocarcinoma is increasing in incidence; it relates to chronic gastroesophageal reflux, it is difficult to cure, and treatment modalities increasingly use chemotherapy and radiation therapy prior to resectional surgery. Nuclear factor-kappa B (NF-kappaB) is a pleiotropic transcription factor that regulates several genes for cytokines and enzymes involved in inflammation and immunity, and we have previously described sequential expression of NF-kappaB from the normal esophagus through Barrett's metaplasia to adenocarcinoma. The aim of this exploratory study was to assess the NF-kappaB status and cytokine profiles pre- and post-chemoradiotherapy for esophageal adenocarcinoma. Fresh biopsy specimens obtained from 20 patients with esophageal adenocarcinoma and normal adjacent squamous epithelium were obtained pre-, during and post-chemoradiotherapy, and NF-kappaB expression was analyzed by electrophoretic mobility shift assay. The cytokine protein content of interleukin-1 beta (IL-1beta) and interleukin-8 (IL-8) of tissue homogenates was measured using the ELISA technique. NF-kappaB was constitutively activated in tumor tissues from esophageal adenocarcinoma but was not detected in adjacent normal esophageal mucosa. Elevated levels of IL-1beta and IL-8 were significantly (P < 0.05) higher in tumor tissues compared to control tissues. Patients with a major or complete pathological response (responders) were associated with absence of activated NF-kappaB from nuclear extracts after treatment. Moreover, IL-1beta and IL-8 levels were significantly (P < 0.05) down-regulated in tumor tissues from patients who demonstrated a complete pathological response. No differences in NF-kappaB, IL-1beta and IL-8 levels were detected pre- and post-treatment in patients who did not have a major or complete pathological response (non-responders). The study suggests that monitoring of molecular and cytokine patterns in patients undergoing this neoadjuvant regimen may help subselect the cohort that derives most benefit from the multimodal approach.

Pseudohyperplastic squamous cell carcinoma of the penis associated with lichen sclerosus. An extremely well-differentiated, nonverruciform neoplasm that preferentially affects the foreskin and is frequently misdiagnosed: a report of 10 cases of a distinctive clinicopathologic entity.

We present 10 cases of well-differentiated, squamous cell carcinoma of the penis with pseudohyperplastic features. At presentation, the median age was 69 years. Seven of the tumors were multicentric, and the majority preferentially involved the foreskin inner mucosal surface. Grossly the tumors were typically flat or slightly elevated, white and granular, and measured approximately 2 cm. Characteristic histologic features included keratinizing nests of squamous cells with minimal atypia surrounded by a reactive fibrous stroma. In biopsies or individual areas of resected specimens, the differential diagnosis with pseudoepitheliomatous hyperplasia was difficult but when samples of adequate size were available, obvious evidence of infiltration was present. The adjacent squamous epithelium typically showed changes that are known to be associated with squamous cell carcinoma ranging from squamous hyperplasia to low-grade, and in a few cases high-grade, squamous intraepithelial lesions. Well-developed lichen sclerosus was seen in all cases. Patients were treated by circumcision or partial penectomy. With the exception of 1 patient who developed a glans recurrence 2 years after initial circumcision, follow-up after the initial surgical procedure has been uneventful. The majority of penile carcinomas with the high degree of differentiation seen in these cases are in the category of the verruciform tumors, either the verrucous or papillary carcinoma, not otherwise-specified subtypes. Experience with the cases reported in this series indicates that a subset of nonverruciform, often multicentric, tumors with a high degree of differentiation and pseudohyperplastic features occur and preferentially involve the foreskin. Because it was present in all cases, lichen sclerosus may play a precancerous role.

Consensus polymerase chain reaction and enzyme-linked immunosorbent assay for human papillomavirus detection and typing in cervical specimens.

Human papillomavirus (HPV) infection is common in cervical intraepithelial neoplasia (CIN). This study investigates HPV detection and typing assay based on polymerase chain reaction amplification of L1 open reading frame with general primers GP5/GP6, followed by enzyme-linked immunosorbent assay detection with type-specific DNA probes. To determine the sensitivity of this assay, formalin-fixed CaSki cells were used as reference cell lines. Fifty copies of viral DNA diluted in DNA from 100,000 noninfected cells could be detected. This assay was also investigated for HPV detection and typing of 67 cervical specimens diagnosed with with CIN III or carcinoma in situ (CIS) and their adjacent squamous epithelium. The CIN III lesions were infected in approximately 80% of the samples, 81% in the neighboring CIN II, and 68% in CIN I. The HPV infection was even detectable in 54% of nondysplastic epithelium located near a CIN III lesion.

Distribution of cytokeratin filaments and vimentin in developing human taste buds.

Taste buds in humans originate from approximately the 8th postovulatory week under the influence of ingrowing nerve fibers. Since they develop from local epithelium, it is of interest whether or not prospective taste cells maintain or develop characteristics of epithelial cells that are different from those of the adjacent epithelium during differentiation. The aim of this study was to monitor changes of the distribution of the cytokeratin filaments (CKs) 8, 18, 19 and 20 ("gastrointestinal" type), CK 7 ("ductal" type), and CK 13 (maturation "mucosa type"), as well as vimentin in developing human taste buds and adjacent squamous epithelium. With the exception of CK13, which remains negative in taste bud anlagen and adult taste buds, all cytokeratins tested were present in taste cells. With the progress of development, the distribution of CKs becomes more and more restricted to taste cells and salivatory ducts as well as Ebner gland cells. Only CK20 is exclusively specific to taste bud anlagen and sometimes to individual bipolar cells occurring in early stages (week 8-9). Vimentin was located mainly in mesodermal derivatives but also in perigemmal epithelial cells during all stages of development. The occurrence of vimentin in "borderline" epithelia that interface with underlying connective tissue, i.e., in a region of discontinuity, may be associated with particular events in development, cell migration or even dedifferentiation.

The histopathology of treated Barrett's esophagus: squamous reepithelialization after acid suppression and laser and photodynamic therapy.

Columnar metaplasia of the lower esophageal epithelium (Barrett's esophagus) occurs in response to acid reflux, and its most important long-term complication is malignancy. In view of this, techniques are being explored for the eradication of Barrett's esophagus, and histopathologists will increasingly be required to assess response to these therapies in esophageal biopsy samples. The histopathologic features before and after treatment were studied in biopsy samples from 16 patients receiving omeprazole only, 10 treated by KTP laser photoablation, and five who underwent photodynamic therapy. All the treatment modalities resulted in histologic changes with at least partial squamous reepithelialization of the metaplastic columnar epithelium. The histologic findings suggest three main mechanisms for this: encroachment of adjacent squamous epithelium at the squamocolumnar junction, extension of epithelium from the submucosal gland duct to form squamous islands, and squamous metaplasia within the Barrett's columnar mucosa itself. The latter mechanism implies the existence of pluripotential stem cells within Barrett's mucosa. A relatively common finding was residual glandular mucosa, nonneoplastic and dysplastic, beneath squamous epithelium indicating the requirement for histologic confirmation of endoscopically suspected complete squamous reepithelialization with sufficiently deep biopsies.

Distribution of cytokeratin markers in Barrett's specialized columnar epithelium

BACKGROUND & AIMS: The cell of origin for Barrett's epithelium is unknown. A multilayered epithelium within Barrett's epithelium has been noted recently. To investigate the hypothesis that this multilayered epithelium may be a transitional stage between squamous and Barrett's epithelium, cytokeratin immunocytochemistry was used to examine normal squamous, Barrett's, and multilayered epithelium.METHODS: Seventeen endoscopic biopsy specimens taken from the squamo-Barrett's junction of 8 patients with Barrett's epithelium and 3 biopsy specimens from the gastroesophageal junction of 3 patients without Barrett's epithelium were investigated. Antibodies to cytokeratins 4 and 13 were used as markers for squamous differentiation, and antibodies to cytokeratins 8 and 19 were used as markers for glandular differentiation. Coded samples were evaluated by immunocytochemistry.RESULTS: In patients with Barrett's epithelium and control patients, staining with columnar markers was confined to either the Barrett's or the gastric columnar epithelium. Staining with squamous markers was confined to the adjacent squamous epithelium. In contrast, focal areas of multilayered epithelium amidst Barrett's epithelium stained with cytokeratin antibodies for both squamous and columnar epithelium.CONCLUSIONS: A focal multilayered epithelium within Barrett's epithelium that expresses concurrently both squamous and glandular cytokeratin markers is described. These findings suggest a multipotential cell as the cell of origin of Barrett's epithelium.(Gastroenterology 1997 Mar;112(3):760-5)

Basaloid Squamous Cell Carcinoma of the Esophagus Immunohistochemistry and Flow Cytometric DNA Analysis in Two Cases

Basaloid squamous cell carcinoma is a well-established anatomopathologic entity of the upper aerodigestive tract and is more aggressive than the conventional squamous cell carcinoma. Only seven cases of this variant have been reported in the esophagus. Two cases of basaloid squamous carcinoma in the middle and lower third of the esophagus in two men aged 59 and 60 years are presented. Tumor stages were IIA and IV at the time of total esophagectomy, and survival times were 34 and 4 months, respectively. Histologically, the two tumors were composed of nests of cells with a basaloid appearance, the first with a predominantly cribriform pattern and the second with a solid lobular pattern and intense comedonecrosis; in the adjacent squamous epithelium of both tumors, carcinoma in situ was observed focally. Immunoreactivity was poor for high-molecular-weight cytokeratins and absent for those of low molecular weight. Staining for epithelial membrane antigen was weakly positive, enolase was moderately positive, and no reactivity for carcinoembryonic antigen, S100 protein, and chromogranin was observed. The flow cytometric analysis showed both tumors to be hyperdiploid with an index of cell proliferation of over 50%.

A comparison of epidermal growth factor receptor (EGFR) and c-erbB-2 oncogene expression in head and neck squamous cell carcinomas

The proto-oncogenes c-erbB-2 and epidermal growth factor (EGF) receptor which encode 2 closely homologous transmembrane glycoproteins have been found amplified and/or overexpressed in a range of epithelial malignancies. In a series of 46 head and neck squamous cell cancers (SCCs), immunohistochemical reactivity for the EGF receptor was detected in all cases, particularly at the invading edge of cellular islands of SCC and in the basal cells of normal adjacent squamous epithelium. Southern blot analysis demonstrated EGF receptor gene amplification in 3 cases. In contrast, strong membrane staining for the c-erbB-2 oncoprotein was not detected in any sample, and there were no cases of c-erbB-2 gene amplification. Despite a close structural and (presumed) functional homology between these 2 receptor-oncoproteins in the development of malignancy, we report that their expression in SCCs is markedly different. Furthermore, unlike the situation for breast cancer, quantitation of the c-erbB-2 or EGF receptor oncoproteins is unlikely to yield important prognostic information in this group of patients.

Cell Proliferation in Esophageal Columnar Epithelium (Barrett’s Esophagus)

In order to correlate histopathology and cell turnover in esophageal tissue in patients with esophageal columnar epithelium, biopsy specimens from 11 patients were studied. Two of the patients had adenocarcinoma of the esophagus not present in the specimens studied. In the heterogeneous esophageal columnar epithelium, the DNA synthesis phase averaged 10.4 +/- 0.3 hr; labeling index of cells in the crypt-like structures was 23.3 +/- 0.3%; generation time was 44.6 +/- 1.2 hr, and the mitotic index was 1.82 +/- 0.07%. Significant differences were not present among specimens with columnar epithelium but they differed from cell proliferation in adjacent squamous epithelium where S phase was similar but labeling and mitotic indexes were lower and generation time increased to 105 +/- 6 hr. In the 2 patients with adenocarcinoma of the esophagus, and in 1 of 9 without adenocarcinoma, labeling of surface columnar cells after brief exposure to [3H]thymidine was present suggests that this may be a manifestation of early malignant change.