Das-1 Reactivity Research Articles

MAb Das-1 identifies pancreatic ductal adenocarcinoma and high-grade pancreatic intraepithelial neoplasia with high accuracy

Pancreatic intraepithelial neoplasia (PanIN) is a microscopic precursor lesion to pancreatic ductal adenocarcinoma (PDAC); however, there are few biomarkers that segregate high-grade PanIN/PDAC from low-grade PanIN lesions. mAb Das-1 is a monoclonal antibody against a colonic epithelial antigen that is reactive to premalignant conditions of the upper gastrointestinal tract including Barrett's esophagus, incomplete-type gastric intestinal metaplasia, and intraductal papillary mucinous neoplasm of the pancreas at high risk of malignancy. We sought to examine a role for Das-1 expression in differentiating high-grade PanIN/PDAC from low-grade PanIN lesions. We examined surgical specimens from 86 patients and 2 autopsied pancreata (74 with and 14 without PDAC) with 107 distinct PanIN lesions, 74 PDAC cases, and 32 associated lymph node metastases, with internal controls of normal pancreatic ducts observed in 56 cases. All of the normal pancreatic duct controls (0/56) and low-grade PanIN (0/95) lesions were nonreactive to Das-1. Das-1 expression amonghigh-grade PanIN (7/12, 58%), PDAC (55/74, 74%), and lymph node metastasis (21/32, 66%) cases was significantly higher (p<0.0001). Clinicopathologically, Das-1 reactivity was significantly correlated with nodal metastasis (p=0.021). Overall, the sensitivity, specificity, and accuracy of Das-1 in segregating high-grade PanIN/PDAC from low-grade PanIN lesions and normal ducts were 72%, 100%, and 90%, respectively. Thus, mAb Das-1 reacts with high specificity with high-grade PanIN and PDAC and may help in preoperative diagnosis and/or clinical risk stratification.

Localization of specialized intestinal metaplasia and the molecular alterations in Barrett esophagus in a Japanese population: an analysis of biopsy samples based on the “Seattle” biopsy protocol

It remains unclear why Barrett esophagus (BE)-associated adenocarcinoma (EAC) frequently occurs in the 0 to 3 o'clock area of the BE. The aims of this study were to clarify the localization of specialized intestinal metaplasia (SIM) as a precancerous lesion and of molecular alterations among different locations using 4-quadrant biopsies based on the "Seattle" protocol. We prospectively evaluated microsatellite instability; methylation status at the APC, CDKN2A, hMLH1, RUNX3, and MGMT genes; the immunoreactivity of the monoclonal antibody Das-1 for the colonic phenotype; and Ki-67 staining in 10 early EACs and 128 biopsy samples from 32 BE patients. Among the molecular changes, only APC gene hypermethylation was an independent predictive marker of EAC (odds ratio, 24.4; P = .01). SIM was more frequently identified in the 0 to 3 o'clock quadrant than in the 6 to 9 o'clock quadrant (P = .08). The Ki-67 index was higher in SIM than in the columnar-lined epithelium (CLE) without goblet cells (P < .0001) and in both SIM and CLE with Das-1 reactivity than in those without (P = .04 and P = .06, respectively). Furthermore, the index was relatively higher in the 0 to 3 o'clock quadrant than in the 6 to 9 o'clock quadrant in cases with Das-1 reactivity. RUNX3 methylation was more frequently found in SIM than in CLE (P = .04), whereas the incidence of the other biomarkers did not show a significant difference between the 0 to 3 o'clock and 6 to 9 o'clock areas, nor between SIM and CLE. SIM with Das-1 reactivity, but not molecular alterations, in the 0 to 3 o'clock quadrant may have higher proliferative activity compared to the other areas of the BE.

Effects of Helicobacter pylori eradication on the development of metachronous gastric cancer after endoscopic treatment: analysis of molecular alterations by a randomised controlled trial.

Background:Whether Helicobacter pylori eradication actually suppresses the development of metachronous gastric cancer (MGC) after endoscopic resection (ER) remains controversial. The aims of this study were to clarify (1) the molecular markers related to carcinogenesis in intestinal metaplasia (IM) by a cross-sectional study, and (2) the changes of those markers by an open-label, randomised controlled trial (RCT) of H. pylori treatment.Methods:First, we evaluated microsatellite instability (MSI), the methylation status at hMLH1, CDKN2A and APC genes, and immunoreactivity using the monoclonal antibody (mAb) Das-1 in IM in the background mucosa of 131 patients who underwent ER for gastric neoplasia and 22 chronic gastritis cases (control). Next, we performed an RCT to evaluate the changes of MSI between the H. pylori-eradicated (n=19) and non-eradicated patients (n=17) at 1 year among the H. pylori-positive patients.Results:Microsatellite instability and mAb Das-1 reactivity showed significantly higher incidences in both the H. pylori-positive and -negative patients compared with the control group, thus suggesting that MSI and mAb Das-1 reactivity are associated with gastric neoplasia (OR=5.06 for MSI; OR=2.51 for mAb Das-1 reactivity). The RCT showed that H. pylori eradication did not provide significant reversals of any molecular alterations including MSI (the primary end point) and other methylation statuses and mAb Das-1 reactivity (secondary end points).Conclusions:H. pylori eradication did not produce significant changes in the molecular alterations related to carcinogenesis, suggesting that H. pylori treatment may not prevent the development of MGC in background mucosa with IM.

Su1933 Investigating the Role of Helicobacter pylori Pria Protein

G A A b st ra ct s suppresses the development of MGC. To clarify the molecular changes due to H. pylori eradication, in this study, we evaluated differences in molecular alterations related to carcinogenesis in background mucosa of GC between H. pylori positive and negative patients. Materials and Methods: Seventy-seven consecutive patients who underwent ER for GC were enrolled. H. pylori status was analyzed in each patient by two methods: Giemsa staining and serum H. pylori-IgG antibody. Biopsy specimens were obtained from all cases, and DNA was extracted from intestinal metaplasia (IM), a precancerous lesion, via laser capture microdissection. Microsatellite instability (MSI) was evaluated at five loci based on the Bethesda panel; promoter methylation at hMLH1, E-cadherin, p16, and APC was assessed using methylation-specific polymerase chain reaction. Reactivity of monoclonal antibody for colonic phenotype (mAb Das-1) to IM was also evaluated by an immunoperoxidase assay. Results: H. pylori status was negative in 32 of 77 participants (41.6%). The incidence of MSI and hypermethylation at hMLH1, E-cadherin, p16, and APC genes in IM for H. pylori positive and negative patients, respectively, were 47.6%, 23.7%, 10.5% and 56.1% and 36.7%, 6.7%, 3.4%, 38.7% and 35.5%. There were no significant differences in molecular alterations between H. pylori positive and negative cases. mAb Das-1 reactivity to IM was 70.5% in H. pylori positive and 71.0% in H. pylori negative patients, demonstrating no significant difference. Conclusions: Early GC occurs frequently even in H. pylori negative patients. There were no significant differences in molecular alterations in IM between H. pylori positive and negative patients, suggesting that H. pylori eradication may not change the course of molecular alterations in background mucosa once GC has occured in the stomach.

Su1932 H. pylori Might Induce TGF-β1-Induced EMT by Way of cagE

G A A b st ra ct s suppresses the development of MGC. To clarify the molecular changes due to H. pylori eradication, in this study, we evaluated differences in molecular alterations related to carcinogenesis in background mucosa of GC between H. pylori positive and negative patients. Materials and Methods: Seventy-seven consecutive patients who underwent ER for GC were enrolled. H. pylori status was analyzed in each patient by two methods: Giemsa staining and serum H. pylori-IgG antibody. Biopsy specimens were obtained from all cases, and DNA was extracted from intestinal metaplasia (IM), a precancerous lesion, via laser capture microdissection. Microsatellite instability (MSI) was evaluated at five loci based on the Bethesda panel; promoter methylation at hMLH1, E-cadherin, p16, and APC was assessed using methylation-specific polymerase chain reaction. Reactivity of monoclonal antibody for colonic phenotype (mAb Das-1) to IM was also evaluated by an immunoperoxidase assay. Results: H. pylori status was negative in 32 of 77 participants (41.6%). The incidence of MSI and hypermethylation at hMLH1, E-cadherin, p16, and APC genes in IM for H. pylori positive and negative patients, respectively, were 47.6%, 23.7%, 10.5% and 56.1% and 36.7%, 6.7%, 3.4%, 38.7% and 35.5%. There were no significant differences in molecular alterations between H. pylori positive and negative cases. mAb Das-1 reactivity to IM was 70.5% in H. pylori positive and 71.0% in H. pylori negative patients, demonstrating no significant difference. Conclusions: Early GC occurs frequently even in H. pylori negative patients. There were no significant differences in molecular alterations in IM between H. pylori positive and negative patients, suggesting that H. pylori eradication may not change the course of molecular alterations in background mucosa once GC has occured in the stomach.

Su1931 Genetic and Serological Predictors of H. pylori Infection in Patients With Inflammatory Bowel Disease

G A A b st ra ct s suppresses the development of MGC. To clarify the molecular changes due to H. pylori eradication, in this study, we evaluated differences in molecular alterations related to carcinogenesis in background mucosa of GC between H. pylori positive and negative patients. Materials and Methods: Seventy-seven consecutive patients who underwent ER for GC were enrolled. H. pylori status was analyzed in each patient by two methods: Giemsa staining and serum H. pylori-IgG antibody. Biopsy specimens were obtained from all cases, and DNA was extracted from intestinal metaplasia (IM), a precancerous lesion, via laser capture microdissection. Microsatellite instability (MSI) was evaluated at five loci based on the Bethesda panel; promoter methylation at hMLH1, E-cadherin, p16, and APC was assessed using methylation-specific polymerase chain reaction. Reactivity of monoclonal antibody for colonic phenotype (mAb Das-1) to IM was also evaluated by an immunoperoxidase assay. Results: H. pylori status was negative in 32 of 77 participants (41.6%). The incidence of MSI and hypermethylation at hMLH1, E-cadherin, p16, and APC genes in IM for H. pylori positive and negative patients, respectively, were 47.6%, 23.7%, 10.5% and 56.1% and 36.7%, 6.7%, 3.4%, 38.7% and 35.5%. There were no significant differences in molecular alterations between H. pylori positive and negative cases. mAb Das-1 reactivity to IM was 70.5% in H. pylori positive and 71.0% in H. pylori negative patients, demonstrating no significant difference. Conclusions: Early GC occurs frequently even in H. pylori negative patients. There were no significant differences in molecular alterations in IM between H. pylori positive and negative patients, suggesting that H. pylori eradication may not change the course of molecular alterations in background mucosa once GC has occured in the stomach.

MAb Das-1 is specific for high-risk and malignant intraductal papillary mucinous neoplasm (IPMN)

ObjectiveIntraductal papillary mucinous neoplasm (IPMN) consists of four epithelial subtypes that correlate with histological grades and risks for malignant transformation. mAb Das-1 is a monoclonal antibody against a colonic epithelial...

Biomarkers predicting development of metachronous gastric cancer after endoscopic resection: an analysis of molecular pathology of Helicobacter pylori eradication.

Metachronous gastric cancer (MGC) after endoscopic resection (ER) of gastric cancer still occurs to some degree even after Helicobacter pylori (H. pylori) treatment. We evaluated whether two biomarkers related to carcinogenesis expressed in intestinal metaplasia (IM) become predictors for MGC development after eradication. We performed a hospital-based, case-control study of 75 patients, including 50 mucosal cancer patients who had undergone ER (Group DYS), and 25 age- and sex-matched chronic gastritis patients for whom H. pylori had been successfully eradicated (control). Additionally, Group DYS patients were divided into two groups: 25 successfully H. pylori-eradicated (eradicated group) and 25 un-eradicated patients (persistent group). All patients were followed for 1 year. We analyzed microsatellite instability (MSI) and immunoperoxidase assays using a monoclonal antibody for the colonic phenotype (Das-1). Both MSI and Das-1 reactivity in IM were significantly higher in Group DYS than in the control (p < 0.05 and p < 0.01, respectively). MSI and Das-1 reactivity were strong and independent predictors for gastric cancer (OR = 7.09, 95% CI 1.27-39.6, p = 0.03 for MSI and OR = 4.96, 95% CI 1.64-15.0, p = 0.005 for Das-1 reactivity). The incidence of MSI tended to decrease in the eradicated group (p = 0.07), but not in the persistent group. The Das-1 immunoreactivity in IM also declined in both the eradicated group and the control. Interestingly, all MGCs after ER were positive for MSI or Das-1 reactivity. MSI or Das-1 reactivity in IM strongly predicts the development of MGC. Patients in whom these biomarkers persist after eradication may therefore have a high risk of developing MGC.

Differences in genetic instability and cellular phenotype among Barrett’s, cardiac, and gastric intestinal metaplasia in a Japanese population with Helicobacter pylori

Intestinal metaplasia is considered to be a precursor lesion in both Barrett's and intestinal-type gastric cancer. The aim was to clarify the differences in molecular pathology between specialized intestinal metaplasia (SIM) in Barrett's oesophagus (BO), cardiac (CIM) and gastric intestinal metaplasia (GIM). Eighty-eight SIM cases with BO, 30 CIM cases and 52 GIM cases in patients with or without Helicobacter pylori infectionwere analysed for genetic instability and Das-1. Microsatellite instability and a loss of heterozygosity were evaluated at five microsatellite loci. The incidence of genetic instability was 55.7% in SIM, 40.0% in CIM and 23.1% in GIM, revealing a significant difference between SIM and GIM (P < 0.0005). For each microsatellite marker analysed, there were obvious differences in frequency among the three conditions. Das-1 reactivity was significantly higher in SIM than in CIM or GIM (P < 0.0001, both). Interestingly, both genetic instability and Das-1 reactivity in SIM showed a significantly higher incidence in patients with H. pylori infection than in those without (P < 0.005 and P < 0.01, respectively). SIM is distinct from CIM and GIM, and the pathogenesis of SIM, like that of GIM, is associated to some degree with H. pylori infection in a Japanese population.

Effects of Helicobacter pylori infection on genetic instability, the aberrant CpG island methylation status and the cellular phenotype in Barrett's esophagus in a Japanese population

Genetic or epigenetic alterations in Barrett's esophagus (BE) with/without Helicobacter pylori (H. pylori) infection remain unclear. We examined the effects of H. pylori infection on genetic instability (GIN), the CpG island methylation status and a biomarker related to BE carcinogenesis. We analyzed 113 Japanese individuals with endoscopically suspected BE. The patients included, Group CLE (n = 25): no specialized intestinal metaplasia (SIM) in a columnar lined epithelium (control); Group BE (n = 88): all had SIM. Microsatellite instability and a loss of heterozygosity as GIN, the methylation status at hMLH1, E-cadherin, p16 and APC, and immunoreactivity using a monoclonal antibody (mAb) Das-1, which specifically reacts with BE, were evaluated. Nine additional patients with BE were prospectively followed up for 2 years after successful H. pylori eradication. The frequency of GIN, methylation at E-cadherin and APC, and mAb Das-1 reactivity in Group BE was significantly higher than that in Group CLE (p < 0.0001, p < 0.0001 and p < 0.005, and p < 0.0001, respectively). Furthermore, GIN, E-cadherin methylation and mAb Das-1 reactivity showed a significantly higher incidence in patients with H.pylori infection than in those without H. pylori infection (p < 0.01, p < 0.005, and p < 0.01, respectively). Interestingly, the patients from Group BE were observed to change to a stable state of molecular alterations in 60% for GIN, 42.9% for E-cadherin methylation and 55.6% for APC methylation, or a reduction of mAb Das-1 reactivity was noted in 25% following eradication. H. pylori infection may therefore affect these molecular alterations associated with the pathogenesis of BE, to some degree, in the Japanese population.

Effect of Eradication of Helicobacter pylori on the Histology and Cellular Phenotype of Gastric Intestinal Metaplasia

Eradication of Helicobacter pylori appears to reduce gastric cancer incidence. We examined the effect of successful H pylori therapy on histology, phenotype of gastric intestinal metaplasia (GIM) (complete vs incomplete), and expression of several biomarkers related to carcinogenesis. Ninety-six H pylori-positive patients from Japan were treated successfully and followed up prospectively over 4 years with yearly endoscopy and were classified into 3 groups: group CG, chronic gastritis without GIM (n = 36); group IM, chronic gastritis with GIM (n = 33); group DYS, and GIM with dysplasia/cancer in a different location of the stomach (n = 27). A total of 288 endoscopic procedures were performed. Histology, mucin-histochemistry, and immunoperoxidase assays using monoclonal antibodies (mAbs) for cell phenotype (monoclonal antibody Das-1/colonic) and for neoplasia (TC22 and p53) were performed. The GIM histologic score was higher in group DYS than in group IM (P < .05) and group CG (P < .0001). The GIM scores did not change in groups IM and DYS over 4 years. mAb Das-1 reactivity was higher in group DYS (63%) than in group IM (39%) and group GC (0%). After eradication of H pylori, mAb Das-1 reactivity disappeared in 40% of patients (P < .0001) despite the unchanged GIM scores, and regression of TC22-4 was noted in the same patients. H pylori eradication does not reduce the histologic GIM score, but changes the cellular phenotype of GIM. This change of phenotype may be an important factor in the reduction of cancer incidence after eradication of H pylori.

Early Diagnosis of Columnar Metaplasia at the Esophagogastric Junction (EGJ) Using a Monoclonal Antibody and Its Reversibility with Proton-Pump Inhibitor (PPI) Therapy

Purpose: Barrett's esophagus (BE) is a known pre-malignant complication of gastroesophageal reflux disease (GERD), and once developed, it is resistant to PPI therapy. A biomarker that might help early diagnosis of metaplasia and allow early initiation of chemoprevention is very much needed. We developed a novel monoclonal antibody, mAb Das-1, that reacts to BE with 100% sensitivity and specificity. It does not react with normal esophagus, EGJ and stomach epithelium. With the use of mAb Das-1, we examined the reversibility of the metaplastic process with PPI therapy. Methods: We have prospectively followed up to 2 years a cohort of 12 patients with GERD who, at initial endoscopic biopsy, showed positive reactivity with mAb Das-1. All patients were treated with PPI. Histological and phenotypic changes on yearly follow-up endoscopy were examined using formalin fixed specimens from the EGJ biopsy tissue. mAb Das-1 reactivity was detected by a sensitive immunoperoxidase assay. Results: Initially, only 5 of 12 patients had histologic columnar metaplasia (CM) and 7 did not, although each of these 12 patients were mAb Das-1 positive. Among these 5 patients with CM, we observed the disappearance of both antibody reactivity and CM in 2 patients. The remaining 3 patients with CM on initial histology continued to have antibody reactivity, although in 2 of the 3 CM disappeared at follow-up biopsy. In only 1 of the 5 patients, CM and mAb Das-1 reactivity persisted during the follow-up. The cohort of 7 of 12 patients exhibited mAb Das-1 reactivity in the absence of CM on initial endoscopy and histology. Five of 7 patients had disappearance of antibody reactivity and there was no CM in subsequent follow-up biopsy. Each of the 5 patients were treated with a PPI, and the treatment course was continuous in 3 and intermittent in 2 patients. Two of the 7 patients with no CM on entry into the study continued to be antibody positive at the time of follow-up. Conclusions: CM, as evidenced by mAb Das-1 reactivity, is present in some patients with symptomatic reflux in the absence of histological evidence of CM. PPI therapy may alter the disease course of this metaplasia if introduced at an early stage and probably with continued therapy.

Molecular Changes at the Esophagogastric Junction (EGJ) in Patients with Symptomatic Gastroesophageal Reflux Disease (GERD) in the Absence of Histological Columnar Metaplasia (CM)

Purpose: We developed a novel monoclonal antibody, mAb Das-1, that recognizes Barrett's epithelium (BE) with 100% sensitivity and specificity. mAb Das-1 reacts with normal colon epithelium but does not react with normal esophagus, EGJ epithelium, gastric or small intestinal epithelium. COX-2 is expressed in the presence of inflammation and in BE. However, expression of these markers at the EGJ in patients with symptomatic GERD with normal histology is unknown. Methods: Patients with symptomatic GERD (N = 86) were enrolled prospectively and 3 to 4 quadrantic biopsy specimens were taken from EGJ during endoscopy. Using immunoperoxidase assays, mAb Das-1 and anti-COX-2 antibody reactivity was assessed in serial sections of paraffin blocks of EGJ biopsy tissue. Thirty-six patients had normal histology, 50 had esophagitis and none had CM. Fourteen samples with adenocarcinoma of the esophagus were included. Normal biopsy specimens from the esophagus (N = 6), small bowel (N = 10) and colon (N = 15) were included as controls. Results: mAb Das-1 reactivity at EGJ was observed in 4 of 36 (11%) patients with normal histology and 7 of 50 (14%) with esophagitis. COX-2 reactivity was found in 9 of 36 (25%) with normal histology and 20 of 50 (40%) with esophagitis. All 14 patients with adenocarcinoma reacted with both mAb Das-1 and anti-COX-2. Three of 4 (75%) patients with mAb Das-1 positivity with normal histology were also reactive to COX-2. COX-2 expression was absent in all control specimens. However, mAb Das-1 reactivity was present in colon epithelium but absent from esophagus and small bowel epithelium. Conclusions: A metaplastic process expressing colonic phenotype of epithelium is found in 13% of EGJ biopsy tissue of symptomatic GERD patients in the absence of histologic CM. COX-2 expression was found in 34% of EGJ tissue of symptomatic GERD patients without CM. These data indicate that subclinical molecular changes at the EGJ, including metaplastic process, occur in some patients with GERD. This strongly supports the existence of a “pre-Barrett's” metaplastic stage. Such molecular diagnosis of early metaplastic process may allow initiation of early interventional treatment against further progression with PPI or other therapy.

Preferential Expression of Cyclooxygenase-2 in Colonic-Phenotype of Gastric Intestinal Metaplasia

Gastric intestinal metaplasia (GIM) associated with H. pylori (HP) has been considered a premalignant lesion. However, GIM phenotype associated with HP infection and gastric cancer is unclear. The expression of COX-2 in relation to GIM phenotype is also unknown. We evaluated cellular phenotype and COX-2 expression in the GIM from HP-positive and -negative patients from Japan in the absence of gastric cancer (n = 31) by using a colon epithelium specific monoclonal antibody (mAb Das-1) and anti-COX-2 antibody. COX-2 expression was also examined in patients with gastric cancer (n = 34), both in the cancer and in the GIM areas away from the cancer field. Sixty-eight percent of HP-positive GIM reacted with mAb Das-1, whereas the reactivity in the HP-negative GIM was only 25% (P < 0.001). The COX-2 expression was present in 32% of HP-positive GIM and in only 9% of HP-negative GIM (P < 0.001). In the cancer group, COX-2 expression was localized both in the cancer area (94%) and in the GIM (82%) away from the cancer. Each of the COX-2-positive tissue was also positive to mAb Das-1. HP infection is highly associated with the development of colonic-phenotype of GIM, and about half of them expressed COX-2. COX-2 expression was frequent in both gastric cancer and the GIM adjacent to the cancer. The results suggest that the presence of mAb Das-1 and COX-2 reactivity in the GIM identify the subgroup of patients who may be at risk for gastric cancer and may need close surveillance.

Phenotype of Barrett's esophagus and intestinal metaplasia of the distal esophagus and gastroesophageal junction: an immunohistochemical study of cytokeratins 7 and 20, Das-1 and 45 MI.

The pathogenesis of short segment Barrett's esophagus (SSBE) and intestinal metaplasia (IM) of the gastroesophageal junction (IMGEJ) are poorly understood. Also, these conditions are difficult to distinguish from one another based solely on endoscopic and pathologic criteria. Therefore, the aim of this study was to evaluate the immunophenotypic features of SSBE and IMGEJ and to compare the results with lesions of known etiologies: long segment BE (LSBE) caused by reflux disease and Helicobacter pylori-induced IM of the gastric antrum (IMGA). Routinely processed mucosal biopsy specimens from 11 patients with LSBE, 17 with SSBE, 10 with IMGEJ, 16 with IMGA, 17 with a normal nonmetaplastic GEJ, and 7 patients with a normal gastric antrum were immunohistochemically stained with monoclonal antibodies to: Das1, an antibody shown to react specifically with colonic goblet cells; 45M1, an antibody that recognizes the M1 gastric mucin antigen; and cytokeratin (CK) 7 and 20, antibodies that have previously been reported to show specific staining patterns in BE versus IMGA. Also evaluated was nonintestinalized mucinous epithelium from LSBE, SSBE, and also the normal GEJ and gastric antrum. LSBE, SSBE, and IMGEJ showed similar prevalences of Das1 (91% versus 88% versus 100%) and 45M1 reactivity (100% versus 100% versus 100%), and a similar pattern of CK7/20 reactivity (diffuse strong CK7 staining of the surface and crypt epithelium, and strong surface and superficial crypt CK20 staining) (91% versus 94% versus 90%). In contrast, although 45M1 reactivity in IMGA (93%) was similar to that of the other three groups, IMGA showed a significantly lower prevalence of Das positivity (13%, p < 0.001), and only a 14% prevalence of the CK7/20 staining pattern that was predominant in the other three groups (p < 0.001). Das1, 45M1, and CK7/20 staining were similar in nonintestinalized "cardia-type" mucinous epithelium from LSBE, SSBE, and the GEJ, but all were distinct from the normal gastric antrum. In summary, the immunophenotypic features of SSBE and IMGEJ are similar and closely resemble those seen in classic LSBE, but are distinct from IMGA. This may indicate that IM in LSBE, SSBE and at the GEJ have similar biologic properties. Based on our data, SSBE and IMGEJ cannot be distinguished on the basis of their immunophenotype.