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PubMed2001

Squamous papilloma of the esophagus: long-term follow up.

BACKGROUND AND AIM: Squamous papilloma of the esophagus is a rare benign tumor; less than 200 cases have been reported in the literature. The prevalence of endoscopically diagnosed squamous papilloma of the esophagus has been reported in only a very few series, and varies from 0.01 to 0.43%. Clinical relevance and possible association with other pathological conditions, namely if it is a premalignant lesion, remain a matter of debate. The etiology is controversial, although a role of human papilloma virus has been recently proposed. The aim of this study was to try to determine the prevalence, clinical relevance, possible association with other pathological conditions of the upper digestive tract, and possible etiological role of human papilloma virus on our series of squamous esophageal papillomas. METHODS: Data from a total of 7618 upper gastrointestinal endoscopies consecutively performed in 4 years were obtained. A 4-year follow up was carried out. RESULTS: Squamous esophageal papilloma was found in nine patients (0.01%). The mean size of polyps was 4 mm and the mean distance from the dental ridge was 25 cm. Only one patient had more than one polyp. Two patients had liver cirrhosis and three had peptic ulcer disease. All squamous esophageal papillomas were removed and tested for human papilloma virus with commercial available kits for in situ hybridization, but none was found positive. CONCLUSION: Squamous papilloma of the esophagus is an uncommon disease that does not appear to predispose to esophageal cancer. No association was found with human papilloma virus.

Adolescent↗

PubMed1995

Squamous endometrial neoplasia-are Fluhmann's postulates still relevant?

A review of squamous neoplasia of the endometrium (in situ and/or invasive) with or without coexistent similar disease of the cervix, revealed four anatomical variants in 22 patients. The patterns were: Group (i), endometrial squamous neoplasia only; Group (ii), discontiguous endometrial and cervical squamous neoplasia; Group (iii), possibly discontiguous endometrial and squamous neoplasia; and Group (iv), contiguous endometrial and squamous disease. The details of the histology, management and outcome are discussed, the latter being much poorer for the fourth group. The criteria for diagnosing squamous neoplasia involving the endometrium are re-examined and a recommendation for these criteria is suggested.

Journal Article↗

PubMed2003

Immunohistochemical visualization of histone H1 phosphorylation in squamous intraepithelial lesions of the gynecologic tract.

Immunohistochemical staining was performed on gynecologic tract squamous intraepithelial lesions using a novel phosphorylation-specific monoclonal antibody (designated 12D11) that detects histone H1 when phosphorylated at a cyclin-dependent kinase (CDK)-responsive epitope. Findings were compared to immunostaining by MIB-1, an extensively studied antibody probe of proliferation. Routinely fixed and processed archival sections were subjected to distinct antigen retrieval and staining protocols for each antibody and were processed for immunodetection of either Ki-67 (with MIB-1) or phosphohistone H1, using a streptavidin-biotin kit and diaminobenzidine as chromagen. For 12D11 staining, antigen retrieval was performed at pH 4.0, and the antibody incubation buffer was supplemented with 1.0 M NaCl. Both 12D11 and MIB-1 stained parabasal cells in normal squamous epithelium. Staining by 12D11 and MIB-1 of cells in progressively higher strata was found to correlate with the severity of lesions. The mean proportion of positively stained cells was higher in MIB-1-stained sections than in 12D11-stained sections in normal squamous epithelium and in all grades of squamous intraepithelial lesions. We conclude that the changes in expression patterns of CDK-phosphorylated histone H1 in the spectrum of gynecologic squamous intraepithelial lesions are similar to staining patterns obtained with the proliferation probe MIB-1. The differing proportion of cells stained by MIB-1 and 12D11 suggests that phosphohistone H1 may be a useful alternative proliferation marker that detects a different subpopulation of cycling cells in premalignant squamous lesions.

Antibodies, Monoclonal↗

PubMed1997

A CACCC box-like cis-regulatory element of the Epstein-Barr virus ED-L2 promoter interacts with a novel transcriptional factor in tissue-specific squamous epithelia.

The Epstein-Barr (EBV) virus induces a lytic state after infecting epithelial cells. Subsequently, there is infection of B lymphocytes with two types of cycles, latent and lytic. Apart from linkage of the EBV latent membrane protein-1 (LMP-1) with benign and malignant conditions of squamous epithelial cells, little is known about other EBV gene products that may be important in these processes as well as cellular transcriptional factors that regulate EBV gene expression in these epithelial cells. The EBV ED-L2 promoter, an early lytic cycle promoter, is located upstream of a transcription start site for a short open reading frame designated BNLF2 and just downstream of the BNLF1 (LMP-1) open reading frame. We have previously used the EBV ED-L2 promoter to target oncogenes in transgenic mice, resulting in tissue-specific expression in the tongue, esophagus, forestomach, and skin, all sharing stratifying squamous epithelia, alternatively called keratinocytes. In the present study, we have functionally dissected the ED-L2 promoter by making deletion constructs fused to the luciferase reporter gene with transient transfections into squamous and nonsquamous epithelial cell lines as well as B lymphocytes. A CACCC box-like cis-regulatory element has been identified that is located between -218 and -187 base pairs of the ED-L2 promoter that confers significant promoter activity only in squamous epithelial cells. This cis-regulatory element is active in a heterologous minimal herpes simplex virus thymidine kinase promoter reporter gene construct when transfected into squamous epithelial cells but not in nonsquamous epithelial cells. DNA gel mobility shift assays have led to the identification of DNA-protein complexes that bind the CACCC box-like element. One of these proteins is a novel transcriptional factor that is uniquely active in stratified squamous epithelial cells, designated as keratinocyte specific factor (KSF). KSF may be related to Sp1 but appears to be distinct from Sp1. In addition, KSF may interact with related or identical cis-regulatory elements found in human papillomavirus-11 E6 and cytokeratin K3 promoters that are active in keratinocytes. In aggregate, KSF may be important in the transcriptional regulation of viral and eukaryotic genes in keratinocytes.

Animals↗

PubMed2007

Prognostic markers of high-grade squamous intraepithelial lesions: the role of p16INK4a and high-risk human papillomavirus.

BACKGROUND: p16INK4a seems to be an indicator of the grade of Human Papillomavirus-induced lesions and a possible predictor of the lesion evolution. There are few studies about the role of HPV test and p16INK4a in diagnosis of high-grade cervical lesions in South-American women. The aim of the present study was to evaluate the presence of p16INK4a and high-risk HPV-DNA expression in cases diagnosed as squamous intra-epithelial lesion and evaluate their role in the approach of high-grade squamous intra-epithelial lesion. METHODS: p16INK4a and high-risk Human papillomavirus were investigated in 96 samples of the cervix (13 cases of high grade squamous intraepithelial lesions, 26 cases of low grade intraepithelial lesions and 57 normal tissues). The p16INK4a was identified by immunohistochemistry using the p16INK4a kit (E6H4 clone, DakoCytomation, Carpinteria, CA) and Human papillomavirus DNA was classified by hybrid capture (Digene). Associations were evaluated by the KAPPA index. RESULTS: The p16INK4a was detected in 92.3% of the high-grade squamous intraepithelial lesions, in 15.4% of the low-grade and in none of the normal tissues. The sensitivity, specificity, positive predictive value and negative predictive value for high-grade lesion were 92.3%, 100%, 100%, and 98.3%, respectively when considering p16INK4a expression, and 100%, 70.2%, 43.3% and 100%, respectively when considering high-risk HPV. CONCLUSIONS: p16INK4a test was better associated with high-grade intraepithelial lesion (kappa = 0.95) than was the presence of high-risk HPV (kappa = 0.47). Both tests could be complementary to high-grade squamous intra-epithelial lesion screening and help to define the diagnosis of the inconclusive low-grade/high-grade squamous intraepithelial lesion cases.

Adult↗

PubMed1998

Reconstitution of squamous epithelium in Barrett's oesophagus with endoscopic argon plasma coagulation: a prospective study.

BACKGROUND: Barrett's oesophagus is a premalignant condition. Recent reports have suggested that laser coagulation or photodynamic therapy combined with acid suppression may induce reconstitution of squamous mucosa. However, a high percentage of residual glands remain in cases treated with both techniques. Argon plasma coagulation (APC) appears to be an attractive alternative to other thermoablative techniques. The aim of this study was to investigate the reconstitution of squamous epithelium in Barrett's oesophagus after APC. METHODS: Fifteen patients with histologically proven Barrett's oesophagus were included in a prospective study. After base-line documentation by videotaping and biopsies, Barrett's epithelium was treated by repeated APC at intervals of 4-6 weeks until complete squamous restoration was achieved. All patients were kept under high-dose proton pump inhibitor therapy. RESULTS: In 13 patients complete reconstitution of squamous epithelium was achieved. Buried glands after squamous restoration were detected transiently in only one case after the first session. As side effects seven patients had mild retrosternal discomfort. One patient reported severe retrosternal pain for 1 week. He then refused further APC sessions. Another patient was excluded because of noncompliance. During the follow-up period (6-13 months) recurrence of Barrett's epithelium was observed in one patient. CONCLUSIONS: APC is a suitable technique for achieving squamous restoration in Barrett's oesophagus. The rare occurrence of remaining buried glands may result from the homogeneous coagulation achieved by the ionized argon gas beam.

Barrett Esophagus↗

PubMed1990

Generation and characterization of a murine monoclonal antibody to cervical glandular epithelium using mice rendered tolerant to cervical squamous epithelium.

Murine monoclonal antibodies that distinguish glandular from squamous epithelia in human tissue were generated using a procedure that involved tolerization prior to immunization. Tolerization was achieved by injection of newborn (24 hrs old) Balb/c mice with extract of normal cervical tissue containing squamous epithelium (the tolerogen). Three weeks later, mice showing no evidence of antibodies to tolerogen in their sera were immunized with an extract of cervical tissue containing both glandular and squamous epithelia. Following immunization, the sera from mice subjected to this treatment showed strong reactivity with glandular cells but not with squamous cells in sections of frozen tissue examined by an indirect immunohistological method. Spleen cells from mice showing this pattern of serum reactivity were used as fusion partners with a mouse myeloma cell line in order to generate monoclonal antibodies. Following extensive screening, one monoclonal antibody (designated anti-GEA.49) was selected for further study on the basis of reactivity with high affinity to glandular epithelium and a complete absence of staining of squamous and connective-tissue cells. Detailed tests of specificity and patterns of reactivity indicate that the antigen detected by the antibody is expressed on the apical plasma membrane of glandular epithelia and is a glycoprotein with an apparent molecular weight of 49 kilodaltons. Both immunohistological and biochemical methods demonstrated the expression of the antigen on glandular epithelia but not on squamous epithelia from several sources, underlining the usefulness of tolerization/immunization approach for generating antibodies with particular specificity requirements.

Animals↗

PubMed1994

The mechanism of the inhibition of squamous differentiation of rat tracheal 2C5 cells by retinoic acid.

Retinoic acid (RA) plays an essential role in maintaining normal differentiation of tracheal epithelial cells. During vitamin A deficiency, tracheocytes undergo squamous metaplasia, an abnormal differentiation that can be reversed by RA. We used rat tracheal 2C5 cells to study the mechanism of inhibition of squamous differentiation by RA. 2C5 cells grown to confluence in the presence of serum underwent squamous differentiation as marked by an increase in their level of crosslinked envelope formation. The serum-induced crosslinked envelope formation was blocked by RA in 2C5 cells with an ED50 < 0.1 nM. However, the activity of the crosslinking enzyme, keratinocyte transglutaminase, did not correlate with the formation of crosslinked envelopes in 2C5 cells. Changes in biochemical markers of squamous differentiation such as an altered expression of specific cytokeratins also accompanied serum-induced squamous differentiation of 2C5 cells. The expression of the keratin squamous differentiation markers (i.e. K13) were inhibited by RA, although the ED50 for K13 expression was > 1 nM. The different dose responses for RA inhibiting differentiation markers suggests multiple mechanisms of regulation by RA. These results indicate that 2C5 cells remain responsive to differentiation factors such as RA and serum despite being an immortalized cell line.

Animals↗

PubMed1998

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.

Aged↗

PubMed1991

Evidence of human papillomavirus deoxyribonucleic acid in vulvar squamous papillomatosis.

Squamous papillae of the vulva represent a controversial lesion. Forty-six women with histologically confirmed vulvar squamous papillae and koilocytosis were studied at Chang Gung Memorial Hospital. Vulvar washings were analyzed by the filter in-situ technique using biotin-labeled probes for typing human papillomavirus DNA. Forty of 46 women (87%) were symptomatic. Human papillomavirus (HPV) DNA was detected in 76% (35 of 46) of women, including type 6/11 in 21.7%, type 16/18/31/33 in 45.6%, and both types in 8.6%. Furthermore, intraepithelial neoplasia was found in the epithelium of squamous papillae in two women. This study suggests the potential value of histologic examination and HPV DNA typing in separating anatomic variation from pathologic squamous papillae. We suggest that those squamous papillae with histologic evidence of koilocytosis be designated as squamous papillomatosis.

Adult↗

PubMed2005

Biologic properties of columnar epithelium underneath reepithelialized squamous mucosa in Barrett's esophagus.

Chronic proton pump inhibitor (PPI) therapy may lead to partial regression of Barrett's esophagus (BE), resulting in the development of reepithelialized islands of squamous mucosa that may cover the underlying BE. The purpose of this study was to evaluate the clinical, histologic, and biologic characteristics of BE that is situated underneath squamous islands (BUSI). A total of 97 mucosal biopsies from 44 BE patients with BUSI were evaluated for a variety of histologic features (eg, type of epithelium, anatomic relationship of the underlying glands to the luminal surface, presence of adjacent mucosal glands or ducts, and the presence and degree of dysplasia), and immunostained for Ki-67, cyclin D1, and p53. BUSI was compared with adjacent areas of BE for all parameters. A clinical control group consisting of 50 BE patients without microscopic evidence of BUSI was selected for comparison of clinical and endoscopic features. The study group (34 males, 10 females; mean age, 67 years; mean length of BE, 5.5 cm) consisted of 27 (61%) and 12 (27%) patients on low- and high-dose PPI, respectively. On endoscopy, visible islands of squamous mucosa were noted in only 43% of study group patients (despite the presence of BUSI microscopically in all cases); one island was noted in 2%, multiple islands in 27%, and extensive islands in 14% of patients. The extent of squamous islands was unrelated to PPI dose. The study group was significantly more likely to have endoscopic evidence of extensive squamous islands compared with the control group (P = 0.009). Histologically, 89% of biopsies with BUSI showed intestinal-type, and 11% showed cardia-type, epithelium. Low- and high-grade dysplasia was noted in 4 (4%) and 5 (5%) biopsies, respectively. All patients with dysplasia in BUSI also showed dysplasia in other areas of the esophagus as well. Interestingly, BUSI reached the mucosal surface either by penetrating directly through, or by wrapping around, islands of squamous epithelium, in 68% of biopsies. Twenty-one percent of biopsies showed BUSI adjacent to submucosal glands or ducts. BUSI showed a significantly lower Ki-67 proliferation rate (29% vs. 49%, P < 0.001), and a lower, albeit nonsignificant, degree of cyclin D1 (16% vs. 29%) and p53 (4% vs. 17%) positivity in comparison to adjacent areas of BE. Furthermore, significantly lower proliferation rates were observed in BUSI that did not reveal an opening to the mucosal surface in comparison to foci that did. BUSI is phenotypically similar to typical surface BE but shows less severe proliferative abnormalities, particularly in buried glands that have no detectable connection to the esophageal lumen. Reduced proliferation may be due either to decreased exposure to luminal contents or to disruption of sloughing of surface epithelial cells into the crypt lumen. Prospective studies of large numbers of patients with BUSI will be required to determine the magnitude of its risk of progression to cancer.

Aged↗

PubMed2007

p16INK4A immunohistochemistry is superior to HPV in situ hybridization for the detection of high-risk HPV in atypical squamous metaplasia.

In situ hybridization (ISH) assays for high-risk human papillomavirus (HR-HPV) and immunohistochemical (IHC) assays for surrogate markers such as p16 can be useful in detecting HR-HPV in cervical dysplasia, but the use of these markers in problematic cervical biopsies has not been well-established. We evaluated 3 chromogenic ISH assays (Ventana INFORM HPVII and HPVIII and DakoCytomation GenPoint) in conjunction with p16 IHC and HPV polymerase chain reaction in a study set consisting of 12 low-grade squamous intraepithelial lesions, 16 high-grade squamous intraepithelial lesions, and 30 benign cervix samples. A test set of 28 cases of atypical squamous metaplasia were also evaluated withVentana HPVIII ISH and p16 IHC. In the study set, the sensitivity of the DakoCytomation ISH assay (which detects HPV subtypes 16, 18, 31, 33, 35, 39, 45, 52, 56, 58, 59, and 68) was similar to the Ventana HPVII assay but less than that of the Ventana HPVIII ISH assay (both of which detect HPV subtypes 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, and 66) and less than p16 IHC (55.6% vs. 53.6 vs. 69.2% vs. 82.1%). All HPV ISH assays exhibited 100% specificity. p16 reactivity consisted of 2 patterns: focal strong and diffuse strong. Because focal strong p16 reactivity was identified in benign squamous epithelium (6.7% cases) and dysplastic epithelium, it was considered an equivocal result and only diffuse strong reactivity was considered to be specific for the presence of HR-HPV. In the squamous intraepithelial lesions study set, the difference in sensitivity between Ventana HPVIII ISH and p16 was not statistically significant. However, in the atypical squamous metaplasia test set cases, p16 reactivity (focal strong and diffuse strong) was significantly more sensitive than Ventana HPVIII ISH in correlating with the presence of human papillomavirus as detected by polymerase chain reaction (83.3% vs. 33.3% P=0.004). Because focal strong p16 reactivity is less specific, cases with this staining pattern are considered atypical and require further evaluation by other means. Overall, p16 IHC is considered the best candidate for the initial assessment of cervical biopsies that are histologically indeterminate for dysplasia given its wide availability, comparative ease of interpretation, and high sensitivity and specificity.

Adolescent↗

PubMed1993

Expression of cornifin in squamous differentiating epithelial tissues, including psoriatic and retinoic acid-treated skin.

The expression of cornifin, a putative cross-linked envelope precursor, was investigated in several squamous differentiating tissues by in situ hybridization and immunohistochemical analysis. Cornifin mRNA and protein, which are absent in the normal mucociliary tracheal epithelium, are induced in the suprabasal layers of the squamous metaplastic tracheal epithelium of vitamin A-deficient hamsters. Similar to the induction of squamous metaplasia in vivo, culture of rabbit tracheal cells in the absence of retinoids results in squamous differentiation and expression of cornifin. This induction of cornifin expression is suppressed by retinoic acid and several of its analogs. Cornifin mRNA and protein are also detected in the suprabasal layers of the squamous epithelium of rabbit esophagus and tongue. The distribution of cornifin in human epidermis was compared with that of two other crosslinked envelope precursor proteins, involucrin and loricrin. The localization of cornifin and involucrin is very similar. Both are induced in the spinous layer and appear at an earlier stage during epidermal differentiation than loricrin. The expression of cornifin is greatly increased in psoriatic skin. Cornifin mRNA is barely detectable in normal epidermis, whereas it is present at relatively high levels in the suprabasal layers of psoriatic epidermis. Topical treatment with RA results in thickening of the skin and increases the level of cornifin mRNA and protein in the upper spinous layers of mouse skin. Cornifin expression correlates generally with squamous differentiation in a variety of tissues and is abnormally regulated in psoriatic skin and in skin treated topically with retinoic acid.

Administration, Topical↗

PubMed1990

The histological and immunohistochemical evidence of squamous metaplasia from the myoepithelial cells in the breast.

Squamous metaplasia in the breast is well documented. However, the putative cell of origin for the squamous epithelium is not clear. This paper describes a case of fibroadenoma of the breast with myoepithelial hyperplasia and squamous metaplasia. The histological finding of transition between myoepithelial cells and squamous cells and the immunohistochemical expressions of actin and S-100 in the metaplastic squamous cells support the myoepithelial origin of squamous epithelium in the breast.

Actins↗

PubMed1992

The predictive value of human papilloma virus (HPV) typing in the prognosis of bronchial squamous cell papillomas.

Five solitary squamous papillomas of bronchus with variable degrees of dysplasia, one combined with a laryngeal papilloma and with a neuroendocrine carcinoma in the contralateral lung, and five papillomas combined with invasive squamous cell carcinomas were investigated for their expression of human papilloma virus DNA by in situ hybridization. Benign squamous cell papillomas showed an association with papilloma virus type 11 and rarely type 6, whereas types 16 or 18, sometimes in combination with types 31/33/35 were found in papillomas associated with carcinomas. In one patient a benign papilloma containing human papilloma virus type 18 and 31/33/35-positive preceded a recurrence combined with carcinoma by 2 years; this recurrent papilloma and the carcinoma were also positive for human papilloma virus 18 DNA. We suggest that human papilloma virus typing should be performed in every squamous cell papilloma of bronchus. Patients with papillomas exhibiting human papilloma virus 16 or 18 positivity are at high risk for the development of squamous cell carcinoma. Furthermore, virus typing may be of prognostic importance in relation to the development of squamous carcinoma.

Aged↗

PubMed1981

Enhancement of squamous cell development in cultured skin by cyclic adenine nucleotide and prostaglandins.

The present study tests the hypothesis that agents known to elevate the level of intracellular cyclic adenine nucleotide may direct different epithelial cells onto a pathway of epidermoid (squamous) development and differentiation. We report here that the mixture of dibutyryl cyclic AMP (dbcAMP), prostaglandins E1, E2 and B1 (PG E1, E2, B1), and papaverine (pap) enhances the rate of normal squamous cell development in organ-cultured skin of chick embryos. The three components may act synergistically to elevate the level of intracellular cyclic adenine nucleotide. We recently reported that the same group of agents induces abnormal development (squamous metaplasia) and aberrant differentiation (keratin production) in the normally cuboidal epithelium of cultured whole mammary glands of mice [1]. Thus, dbcAMP, PG E1, E2, B1, and pap are effective in enhancing normal squamous cell development and also in inducing squamous metaplasia de novo in the epithelial components of two different organs of embryonic and adult animals of two classes of vertebrates. The combined findings are suggestive that cyclic adenine nucleotide together with the prostaglandins may act generally on diverse types of epithelia to bring about squamous cell development and a differentiation marked by keratin production.

Aldosterone↗

PubMed1988

Human bronchial epithelial cells with integrated SV40 virus T antigen genes retain the ability to undergo squamous differentiation.

Human bronchial epithelial cells transformed by either DNA virus infection (SV40 or Adenovirus 12-SV40 hybrid virus) or transfection with the SV40 large T antigen gene were studied for their ability to undergo squamous differentiation when exposed to 12-O-tetradecanoylphorbol-13 acetate (TPA), transforming growth factor-beta 1 (TGF-beta 1), or fetal bovine serum (FBS), agents that induce the squamous differentiation of normal human bronchial epithelial cells. Squamous differentiation occurred in all ten T-antigen-positive cell cultures when they were exposed to either FBS or TGF-beta 1, but none differentiated when exposed to TPA. From one cell line, designated BEAS-2B, two subclones were isolated, one of which was induced to undergo squamous differentiation by FBS, and a second that failed to undergo squamous differentiation and was mitogenically stimulated when exposed to serum. These phenotypically different subclones provide a new in vitro cellular system for delineating the mechanism(s) of human bronchial epithelial cell squamous differentiation in response to FBS or TGF-beta 1.

Antigens, Viral↗

PubMed2006

Cdx-2 expression in squamous and metaplastic columnar epithelia of the esophagus.

The molecular pathogenesis of Barrett's esophagus is poorly understood. Evidence suggests that at a phenotypic level, the metaplastic process begins with the transformation of squamous epithelium in the distal esophagus to cardiac mucosa, which subsequently becomes intestinalized. The homeobox gene Cdx-2 has been shown to be an important transcriptional regulator of embryonic differentiation and maintenance of adult intestinal type epithelium. We hypothesized that Cdx-2 gene expression levels increase with the phenotypic transformation of normal squamous mucosa to the intestinalized columnar mucosa of Barrett's esophagus. Endoscopic biopsies were obtained at the gastroesophageal junction in patients with symptoms of gastroesophageal reflux disease and classified according to histology: normal squamous mucosa (n = 62), cardiac mucosa (n = 19), oxynto-cardiac mucosa (n = 14), and intestinal metaplasia (n = 15). Duodenal biopsies (n = 26) served as the columnar control. After laser capture microdissection and RNA isolation, gene expression levels of Cdx-2 were measured in each tissue type by quantitative reverse transcription polymerase chain reaction. Consistent with its known function, Cdx-2 gene expression levels were highest in duodenal mucosa and nearly absent in squamous epithelium. There was a stepwise increase in Cdx-2 gene expression from cardiac to Barrett's epithelium (P < 0.001). Expression levels of Cdx-2 in cardiac and oxynto-cardiac mucosa were 40-70 times higher and Barrett's mucosa 400 times higher than that found in squamous epithelium. Relative expression of the homeobox gene Cdx-2, known to induce differentiation of intestinal type epithelium, increases in a stepwise fashion during the phenotypic transformation of distal esophageal squamous mucosa to cardiac columnar mucosa and to the intestinalized columnar mucosa of Barrett's esophagus. Therefore, Cdx-2 may be a potential biomarker to detect the early transition to Barrett's esophagus.

Adolescent↗