Colorectal cancer screening and surveillance in Crohn's colitis

AIMS

To assess colonoscopic screening and surveillance for detecting neoplasia in patients with long-standing colonic Crohn's disease (CD).

PATIENTS AND METHODS

Colonoscopy and biopsy records from patients with colonic CD were evaluated at the Cedars-Sinai Inflammatory Bowel Disease Center during a 17-year period (1992-2009).

RESULTS

Overall, 904 screening and surveillance examinations were performed on 411 patients with Crohn's colitis (mean 2.2 examinations per patient). The screening and surveillance examinations detected neoplasia in 5.6% of the patient population; 2.7% had low-grade dysplasia (LGD) (n=11), 0.7% had high-grade dysplasia (HGD) (n=3), and 2.2% had carcinoma (anal carcinoma n=3; rectal carcinoma n=6). Mean age of CD diagnosis was 25.6±0.8 years in those with normal examinations, compared to 17.7±2.7 years (p<0.001) in those with HGD, 36.85±1.43 in those with LGD (p=0.021) and 28.32±3.24 years in those with any dysplasia/cancer (p=0.034). Disease duration in patients with normal examinations was 19.1±0.5 years, compared to 36.8±4.4 years (p<0.001) in HGD, 16.88±2.59 in those with LGD (p=0.253) and 30.68±4.03 years in those with any dysplasia/cancer (p=0.152). The mean interval between examinations was higher in HGD (31.5±9.4 months) compared to those with normal colonoscopies (12.92±1.250 months; p=0.002).

CONCLUSIONS

We detected cancer or dysplasia in 5.6% of patients with long-standing Crohn's colitis enrolled in a screening and surveillance program. Younger age at diagnosis of CD, longer disease course, and greater interval between exams were risk factors for the development of dysplasia.

The significance of "indefinite for dysplasia" grading in Barrett metaplasia

CONTEXT

For a confident diagnosis of dysplasia in Barrett metaplasia, the epithelial atypia should also involve the surface epithelium. However, pathologists are often faced with biopsies where the crypts show dysplasia, but the surface epithelium is either uninvolved or unevaluable. We previously grouped these cases with indefinite for dysplasia (IND).

OBJECTIVE

To determine the clinical significance of IND grading in Barrett metaplasia.

DESIGN

All biopsies from 276 prospectively followed patients with Barrett metaplasia, who did not have high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) on initial biopsy, were graded as negative for dysplasia, IND, low-grade dysplasia (LGD), HGD, and EAC. Biopsies with multifocal IND or LGD were graded as INDM or LGDM, respectively.

RESULTS

Only 3 of 193 patients (2%) with an initial diagnosis of negative for dysplasia and only 1 of 48 patients (2%) diagnosed with IND progressed to HGD or EAC. By contrast, 1 of 7 patients (14%) with INDM, 2 of 21 (10%) with LGD, and 1 of 7 (14%) with LGDM progressed to HGD or EAC. There was no significant difference in progression rate between patients with an initial diagnosis of negative for dysplasia and those diagnosed IND nor were there significant differences among patients with initial diagnoses of INDM, LGD, or LGDM. Kaplan-Meier analysis showed that patients with INDM, LGD, or LGDM on initial biopsy (group 1) were more likely to progress to HGD or EAC than were those patients who were diagnosed negative for dysplasia or IND (group 2; log-rank test, P < .001).

CONCLUSIONS

Multifocal IND in an esophageal biopsy from a patient with Barrett metaplasia has the same clinical implication as LGD.

The significance of "indefinite for dysplasia" grading in Barrett metaplasia

CONTEXT

For a confident diagnosis of dysplasia in Barrett metaplasia, the epithelial atypia should also involve the surface epithelium. However, pathologists are often faced with biopsies where the crypts show dysplasia, but the surface epithelium is either uninvolved or unevaluable. We previously grouped these cases with indefinite for dysplasia (IND).

OBJECTIVE

To determine the clinical significance of IND grading in Barrett metaplasia.

DESIGN

All biopsies from 276 prospectively followed patients with Barrett metaplasia, who did not have high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) on initial biopsy, were graded as negative for dysplasia, IND, low-grade dysplasia (LGD), HGD, and EAC. Biopsies with multifocal IND or LGD were graded as INDM or LGDM, respectively.

RESULTS

Only 3 of 193 patients (2%) with an initial diagnosis of negative for dysplasia and only 1 of 48 patients (2%) diagnosed with IND progressed to HGD or EAC. By contrast, 1 of 7 patients (14%) with INDM, 2 of 21 (10%) with LGD, and 1 of 7 (14%) with LGDM progressed to HGD or EAC. There was no significant difference in progression rate between patients with an initial diagnosis of negative for dysplasia and those diagnosed IND nor were there significant differences among patients with initial diagnoses of INDM, LGD, or LGDM. Kaplan-Meier analysis showed that patients with INDM, LGD, or LGDM on initial biopsy (group 1) were more likely to progress to HGD or EAC than were those patients who were diagnosed negative for dysplasia or IND (group 2; log-rank test, P < .001).

CONCLUSIONS

Multifocal IND in an esophageal biopsy from a patient with Barrett metaplasia has the same clinical implication as LGD.

P16 and Ki67 Immunostains Decrease Intra- and Interobserver Variability in the Diagnosis and Grading of Anal Intraepithelial Neoplasia (AIN)

BACKGROUND

Significant variation is reported in the diagnosis of HPV-associated AIN. We previously observed that band-like positivity for p16 in >90% of contiguous cells coupled with Ki67 positivity in >50% of lesional cells is strongly associated with high grade AIN. This study was undertaken to determine if addition of p16 and Ki67 immunostaining would reduce inter- and intraobserver variability in diagnosis and grading of AIN.

DESIGN

H&E stained slides of 60 anal biopsies were reviewed by three pathologists and consensus diagnoses were achieved: 25 negative, 12 low (condyloma and/or AIN I) and 23 high (9 AIN II and 14 AIN III) grade lesions. The H&E stained slides were diagnosed independently by three additional ("participant") pathologists. Several weeks later they re-examined these slides in conjunction with corresponding p16 and Ki67 immunostains.

RESULTS

Addition of p16 and Ki67 immunostains reduced intra- and interobserver variability, improved concurrence with consensus diagnoses and reduced two-step differences in diagnosis. Negative and high grade AIN diagnoses showed the most improvement in concurrence levels.

CONCLUSION

Addition of p16 and Ki67 immunostains is helpful in the diagnosis and grading of AIN.

Goblet cell mimickers in esophageal biopsies are not associated with an increased risk for dysplasia

CONTEXT

Identification of intestinal-type goblet cells (ITGCs) in hematoxylin-eosin-stained sections of esophageal biopsies is essential for the diagnosis of Barrett metaplasia. However, we have seen cases diagnosed as Barrett metaplasia based solely on cells that pose morphologic similarity to ITGCs on hematoxylin-eosin staining or stain positive with Alcian blue.

OBJECTIVE

To determine the clinical significance of goblet cell mimickers.

DESIGN

Initial biopsies from 78 patients with original diagnosis of Barrett metaplasia negative for dysplasia and a mean follow-up of 72 months were reviewed and reclassified into 3 categories: (1) ITGCs, (2) goblet cell mimickers, or (3) neither. Sections from available paraffin blocks were stained with Alcian blue at pH 2.5. The presence of the different types of cells and positive Alcian blue staining were correlated with each other and evaluated for their significance as predictors of progression to dysplasia.

RESULTS

Goblet cell mimickers were present in 35 cases and were associated with ITGCs in the same biopsy in 23 (66%) of these cases. Intestinal-type goblet cells were present in 56 cases, and the remaining 10 cases, although called Barrett on the original report, did not show either ITGCs or goblet cell mimickers. Only the presence of ITGCs was associated with significant risk for dysplasia (P = .008). Positive Alcian blue staining was not associated with a significant risk for dysplasia.

CONCLUSIONS

Our results indicate that the diagnosis of Barrett metaplasia should be rendered with confidence only when ITGCs are identified on routine hematoxylin-eosin-stained sections.

Primary hepatic carcinoid tumor presenting as Cushing's syndrome

Hepatic carcinoid tumors are very uncommon; most are clinically non-functional and very few present with the symptoms of carcinoid syndrome. ACTH-producing carcinoid tumors most commonly originate in the lung or thymus and present insidiously with bronchospasm and/or chest mass. Occasionally, ectopic ACTH syndromes have been reported in association with pancreatic islet cell tumors, medullary thyroid cancer, pheochromocytoma, small-cell lung carcinoma, and rarely, ovarian and prostate tumors. We report here a patient with an ectopic ACTH-secreting primary hepatic carcinoid tumor who presented with cushingoid appearance, profound proximal muscle weakness, severe lower extremity edema, and markedly elevated urinary free cortisol. ACTH levels were in the low normal range. A solitary vascular hepatic lesion was found on magnetic resonance imaging, which was isodense with the surrounding liver on octreotide scan and photopenic on an 18-fluorodeoxyglucose (18FDG)-positron emission tomography (PET) scan. Following surgical resection of the hepatic tumor, histopathology confirmed an ACTH-secreting neuroendocrine tumor (NET), the patient had complete resolution of hypercortisolemic symptoms and remains in remission, now 4 yr after hepatic tumor resection. This case reports the first ACTH-secreting primary hepatic NET presenting as ectopic Cushing's syndrome. Interesting aspects of this case include the presence of a pituitary incidentaloma, the low normal ACTH, and photopenia on 18FDG-PET imaging.

P16 and Ki67 Immunostaining is a Useful Adjunct in the Assessment of Biopsies for HPV-Associated Anal Intraepithelial Neoplasia

P16 is a tumor suppressor gene product, shown to be overexpressed in most cervical carcinomas and dysplasias associated with high-risk human papilloma virus (HPV) infection. HPV is also associated with anal squamous dysplasias and carcinomas. Significant interobserver and intraobserver variation exists in the interpretation of biopsies for anal intraepithelial neoplasia (AIN). This study was undertaken to assess the potential role of p16 and Ki67 immunohistochemical expression in refining the diagnosis and grading of AIN.One-hundred and four anal biopsies from 74 patients were retrieved from the surgical pathology files of the department. After discrepancies were resolved and concurrence was achieved by at least 2 of 3 reviewing pathologists, the diagnoses were as follows: 37 negative, 12 condylomas without overt dysplasia, 14 AIN I, 25 AIN II, and 16 AIN III. p16 and Ki67 expression was evaluated by ABC immunoperoxidase staining whereas the presence of the high-risk subtypes of HPV virus was determined by in situ hybridization on a subset of the biopsies. Results were reviewed by 2 pathologists and positive and negative staining was correlated with H&E diagnoses. Nuclear and/or nuclear and cytoplasmic staining was considered as positive for p16 when present in >10% of squamous cells. Two patterns of positive p16 staining were observed: (1) "spotty" in which positive cells were scattered throughout the lesion and (2) "band" in which >90% of contiguous cells in the lesion stained positive. A band-like pattern of p16 immunoreactivity was seen in 21.4% AIN I, 80% AIN II, and 87.5% AIN III cases. None of the condylomas and only 1 of the negative cases showed a band of p16 positive staining. Spotty p16 immunoreactivity was observed in 8.1% negative, 8.3% condyloma, 14.3% AIN I, 12.0% AIN II, and 12.5% AIN III cases. More than 50% of nuclei stained positive for Ki67 in 28.6% AIN I, 48.0% AIN II, and 75.0% AIN III cases but in none of the negative or condyloma cases. On the basis of these results, a band-like pattern of p16 staining and Ki67 positivity in >50% of the squamous cell nuclei were strongly associated with high-grade AIN. Conversely, absence of a p16 band of positivity coupled with Ki67 positivity in <50% of nuclei was frequently associated with benign lesions. Band like p16 staining also correlated strongly with the presence of high-risk HPV. Most AIN I lesions stained similar to the nondysplastic cases. A small subset of biopsies studied did not conform to the pattern described above: 4 of 14 (28.6%) AIN I lesions showed a band-like pattern of p16 staining and/or >50% Ki67 positive nuclei. Two of these cases were positive for high-risk HPV DNA. 4 of 25 (16.0%) AIN II lesions comprising 9.8% of the 41 high-grade AINs (AIN II and III) showed spotty p16 positivity and <50% Ki67 positive nuclei. One was positive for high-risk HPV DNA. We conclude that when used together and evaluated in conjunction with H&E stained sections, p16 and Ki67 immunoexpression is a useful adjunct in the diagnosis and grading of AIN.

Frozen section examination of liver, gallbladder, and pancreas

CONTEXT

Frozen section of the liver is a comparatively frequent request that most often applies to a relatively limited number of situations. The only indication for frozen tissue examination of a gallbladder with any frequency is the presence of a polypoid mucosal lesion or a suspicious thickening of the gallbladder wall. A variety of intraoperative consultations may be applicable during surgery of the pancreas.

OBJECTIVE

To examine the indications and pitfalls regarding the gross examination and frozen section performance for liver, gallbladder, and pancreas.

DATA SOURCES

Author experience and review of the pertinent literature.

CONCLUSIONS

Although indications are relatively straightforward for frozen section of liver and gallbladder, handling of the pancreas specimens for frozen tissue examination is often a cause for a certain degree of anxiety. This situation is the result of a relative rarity of such specimens outside large tertiary referral medical centers coupled with a variety of confounding factors, including the presence of chronic pancreatitis with distortion of the normal structures and the frequent presence of variable degrees of dysplasia. The suboptimal preservation of the frozen tissue adds further angst to the scenario. In this article, the main issues are critically examined in light of the experience of the author and others.

Toll-like receptor-4 is required for intestinal response to epithelial injury and limiting bacterial translocation in a murine model of acute colitis

Inflammatory bowel disease (IBD) arises from a dysregulated mucosal immune response to luminal bacteria. Toll-like receptor (TLR)4 recognizes LPS and transduces a proinflammatory signal through the adapter molecule myeloid differentiation marker 88 (MyD88). We hypothesized that TLR4 participates in the innate immune response to luminal bacteria and the development of colitis. TLR4-/- and MyD88-/- mice and littermate controls were given 2.5% dextran sodium sulfate (DSS) for 5 or 7 days followed by a 7-day recovery. Colitis was assessed by weight loss, rectal bleeding, and histopathology. Immunostaining was performed for macrophage markers, chemokine expression, and cell proliferation markers. DSS treatment of TLR4-/- mice was associated with striking reduction in acute inflammatory cells compared with wild-type mice despite similar degrees of epithelial injury. TLR4-/- mice experienced earlier and more severe bleeding than control mice. Similar results were seen with MyD88-/- mice, suggesting that this is the dominant downstream pathway. Mesenteric lymph nodes from TLR4-/- and MyD88-/- mice more frequently grew gram-negative bacteria. Altered neutrophil recruitment was due to diminished macrophage inflammatory protein-2 expression by lamina propria macrophages in TLR4-/- and MyD88-/- mice. The similarity in crypt epithelial damage between TLR4-/- or MyD88-/- and wild-type mice was seen despite decreased epithelial proliferation in knockout mice. TLR4 through the adapter molecule MyD88 is important in intestinal response to injury and in limiting bacterial translocation. Despite the diversity of luminal bacteria, other TLRs do not substitute for the role of TLR4 in this acute colitis model. A defective innate immune response may result in diminished bacterial clearance and ultimately dysregulated response to normal flora.

Paneth Cell Carcinoma of the Ampulla of Vater

We describe a Paneth cell carcinoma arising within the ampulla of Vater in a 64-year-old man. The phenotype of virtually all neoplastic cells was consistent with that of Paneth cells, based on routine morphology and their strong positive immunostaining for lysozyme. Additional widespread positive immunostaining for carcinoembryonic antigen and CA 19.9 supports a totipotential cell as the origin of such neoplastic cells. This case, therefore, represents a true Paneth cell carcinoma, as opposed to inclusion of occasional neoplastic Paneth cells into a poorly differentiated adenocarcinoma. This pattern of differentiation is rare, and predictions regarding its ultimate biological behavior and malignant potential must be guarded.

Thyroid carcinoma arising from a sacrococcygeal mass: a malignant teratoma?

A 59-year-old African American male with a remote history of Graves' disease presented with a 13-cm sacrococcygeal mass that was resected. Pathologic examination revealed this to be papillary thyroid carcinoma with large areas of hemorrhage and necrosis. No other teratomatous elements were identified. The patient underwent extensive evaluation of the thyroid gland with ultrasound, computed tomography (CT) scan, and laboratory studies without any evidence of thyroid mass or malignancy. In addition, further evaluations with chest/abdominal/pelvic CT as well as a bone scan failed to reveal any evidence of metastatic disease. At 1-year follow-up, the patient has remained euthyroid and without evidence of recurrence. We believe that our patient may represent the first reported case of malignant transformation of mature thyroid tissue in a sacrococcygeal teratoma. The impact of his diagnosis on the decision-making for performing a total thyroidectomy is discussed.

A pilot study of adalimumab in infliximab-allergic patients

The anti-TNF-alpha antibody infliximab (Remicade) is highly effective in the treatment of Crohn's disease. A subset of patients experience allergic reactions as a result of antibodies to infliximab (ATIs). The purpose of the current study is to describe the safety and efficacy of adalimumab (Humira) in patients previously allergic or intolerant to infliximab. Adalimumab is an anti-TNF-alpha agent containing only human peptide sequences. Seven patients have been treated with adalimumab who had experienced immediate- or delayed-hypersensitivity reactions to infliximab and one with infliximab-induced lupus. Except for injection site discomfort, adalimumab was well tolerated without signs or symptoms of allergic reactions. One patient who had previously received pooled human immunoglobulin developed a pruritic rash after each dose of adalimumab. Patients with active disease who had previously experienced a robust response to infliximab responded to adalimumab as reflected by an improvement in Harvey-Bradshaw index and inflammatory markers. Based on these preliminary data, adalimumab may be a safe and effective substitute for infliximab-allergic patients. Individuals who have been exposed to human antibodies may be sensitized to other human antibodies such as adalimumab.

Expression of the high mobility group proteins HMGI(Y) correlates with malignant progression in Barrett's metaplasia

Expression of the high mobility group proteins HMGI(Y) has been shown to be a marker of malignancy in thyroid and pancreatic lesions and to correlate significantly with malignant progression in the colon. The aim of this study was to determine whether HMGI(Y) expression is associated with malignant progression in Barrett's metaplasia (BM). Immunoperoxidase staining for HMGI(Y) was performed on sections of formalin-fixed paraffin-embedded endoscopic esophageal biopsies from 42 patients with BM. These consisted of 19 biopsies negative for dysplasia (ND), 16 with low-grade dysplasia (LGD)/indeterminate for dysplasia (IND), and 7 with high-grade dysplasia (HGD)/adenocarcinoma (CA). The percentage of positive cells was recorded, and nuclear HMGI(Y) immunoreactivity in >10% of the cells was considered positive. Statistical analysis was performed using Fisher's exact test. Positive HMGI(Y) staining was detected in 2 of 19 (11%) cases ND, 5 of 16 (30%) LGD/IND cases, and 7 of 7 (100%) HGD/CA cases. Biopsies with HGD/CA were significantly more likely to be positive for HMGI(Y) than biopsies ND (P < 0.0001) or with LGD/IND (P = 0.0046). We conclude that HMGI(Y) expression is significantly associated with malignant progression in BM. Additional studies are needed to determine whether BM biopsies that are ND or LGD/IND and positive for HMGI(Y) are more likely to progress to adenocarcinoma.

Intraoperative consultation for renal lesions. Implications and diagnostic pitfalls in 324 cases

Intraoperative consultation rarely is requested for lesions in the kidney. Of 324 renal lesions submitted for gross or frozen section intraoperative consultation, 199 specimens were submitted for gross consultation only; no diagnostic pitfalls were noted. The clinical implications and diagnostic pitfalls in 125 specimens submitted for frozen section were the focus of our study. Frozen section intraoperative consultation was requested to evaluate surgical margins in partial nephrectomy specimens, solid renal mass in an unusual clinical or radiologic setting, synchronous renal and extrarenal masses, cystic renal lesion, ureteral surgical margins for transitional cell carcinoma, multiple renal masses, solid mass in a diffusely cystic kidney, and renal injury. Among the 125 cases, the diagnoses were deferred in 17 (6 renal cell carcinomas with granular cytoplasm, 7 cystic lesions, 3 metastatic tumors, 1 leiomyoma). The frozen section diagnoses were incorrect owing to limited sampling in 5 and misinterpretation in 4 (melanoma vs angiomyolipoma, lymphoma vs angiomyolipoma, benign cyst vs cystic renal cell carcinoma, metastatic renal cell carcinoma vs pheochromocytoma). Awareness of distinctive indications for frozen section intraoperative consultation and diagnostic pitfalls should improve diagnostic accuracy and facilitate proper management of these lesions.

Pancreatic acinar cell metaplasia in autoimmune gastritis

OBJECTIVE

To determine the frequency and significance of pancreatic acinar cells in the gastric oxyntic mucosa.

DESIGN

One hundred gastric oxyntic mucosal biopsy specimens from patients with chronic active gastritis (n = 30), multifocal atrophic gastritis (n = 15), autoimmune gastritis (n = 18), and normal gastric oxyntic mucosa (n = 37) were evaluated for the presence of pancreatic acinar cells. Formalin-fixed, paraffin-embedded tissues were stained with hematoxylin-eosin, and those positive for pancreatic acinar cells were immunostained with antibodies against trypsin and pancreatic amylase.

RESULTS

Eleven (11%) of 100 oxyntic mucosal tissue samples contained pancreatic acinar cells. These samples came from 9 of the 18 (50%) specimens of autoimmune gastritis, 1 of the 15 (6.6%) specimens of multifocal atrophic gastritis, and 1 of the 37 (2.7%) specimens of normal oxyntic mucosa. None of the samples with chronic active gastritis contained pancreatic acinar cells.

CONCLUSIONS

Pancreatic acinar cells were found in the oxyntic mucosa of patients with autoimmune gastritis significantly more frequently (P <.001) than in individuals with multifocal atrophic gastritis, normal oxyntic mucosa, or chronic active gastritis. Our study supports a metaplastic origin for pancreatic acinar cells in the oxyntic mucosa. Furthermore, detection of pancreatic acinar cells in the oxyntic mucosa of patients with gastritis strongly suggests an autoimmune pathogenesis.

Non-dysplastic and dysplastic Barrett's mucosa and adenocarcinoma lack a subepithelial myofibroblastic cell layer

A subepitheal myofibroblastic (SMF) cell layer has been described in the colon, and referred to as pericryptal myofibroblastic cell layer. SMF cells have been shown to produce basement membrane proteins, including type IV collagen and laminin. The aim of this work was to determine the status of the SMF cell layer in Barrett's metaplasia (BM), with and without dysplasia, and compare that to the previously reported distribution of SMF in normal colon and colonic adenomas and carcinoma. Sections of formalin-fixed, paraffin-embedded biopsies from 6 colonic adenomas and 5 colonic adenocarcinomas, as well as 4 cases of BM without dysplasia, 4 with low grade dysplasia, 4 high grade dysplasia and 4 with invasive adenocarcinoma were immunohistochemically stained for alpha smooth muscle actin using the immunoperoxidase method. A continuous layer of SMF cells was present in all normal colonic tissue and adenomas but was absent in all colorectal adenocarcinomas. Surprisingly, none of the cases of BM with or without dysplasia or carcinoma showed an organized SMF cell layer. Unlike the colon, the SMF cell layer is absent in BM even without dysplasia. We hypothesize that lack of the SMF cell layer in BM may contribute to the quick progression to esophageal adenocarcinoma, which, unlike that in the colon, occurs before an exophytic lesion becomes evident.

Gastric mucosal atrophy: interobserver consistency using new criteria for classification and grading

BACKGROUND AND AIMS

Considerable difficulties persist amongst pathologists in agreeing on the presence and severity of gastric atrophy. An international group of pathologists pursued the following aims: (i) to generate an acceptable definition and a simple reproducible classification of gastric atrophy; and (ii) to develop guidelines for the recognition of atrophy useful for increasing agreement among observers.

METHODS

After redefining atrophy as the 'loss of appropriate glands' and examining histological samples from different gastric compartments, three categories were identified: (i) negative; (ii) indefinite; (iii) atrophy, with and without intestinalization. Atrophy was graded on a three-level scale. Interobserver reproducibility of the classification was tested by kappa statistics (general and weighted) in a series of 48 cases.

RESULTS

The medians of the general agreement and weighted kappa values were 0.78 and 0.73, respectively. The weighted kappa coefficients, obtained by cross-tabulating the evaluation of each pathologist against all others, were, with only one exception, > 0.4 (moderate to excellent agreement).

CONCLUSIONS

By using the definition of atrophy as the loss of appropriate glands and distinguishing the two main morphological entities of metaplastic and non-metaplastic types, a high level of agreement was achieved by a group of gastrointestinal pathologists trained in different cultural contexts.

Acid suppression therapy may not alter malignant progression in Barrett's metaplasia showing p53 protein accumulation

OBJECTIVES

Several previous studies have shown that malignant progression in Barrett's metaplasia (BM) occurs even in patients treated with fundoplication or acid suppression therapy (AST). The aim of this study was to test the hypothesis that AST may not alter malignant progression in BM if key genes involved in DNA repair and cell cycle control, particularly p53, are defective.

METHODS

Initial and follow-up biopsies from 21 patients with BM treated with AST and observed for 1-13 yr were entered in the study. All biopsies were graded for dysplasia and evaluated for p53 protein accumulation and oxidative DNA damage by immunohiostochemistry, using antibodies to p53 and to 8-hydroxydeoxyguanosine, respectively. DNA ploidy was determined using image analysis. Statistical analysis was performed using Kaplan-Meier curves, log rank test, and multivariate regression.

RESULTS

Patients with p53 positive initial biopsies were more likely to have progression in dysplasia grade (p = 0.022) and DNA ploidy status (p = 0.023) than those with p53 negative biopsies. In eight patients AST resulted in significant reduction in oxidative DNA damage in the five patients with p53-negative initial biopsies, but not the three with p53 positive ones (p = 0.0007).

CONCLUSIONS

We conclude that failure of AST to alter malignant progression in BM may be due, at least in part, to defects in DNA repair and cell cycle control resulting from p53 gene mutation, present before AST treatment. Although AST may be effective in preventing further DNA damage, it is unlikely to alter progression in genetically unstable cells.

Acid suppression therapy may not alter malignant progression in Barrett's metaplasia showing p53 protein accumulation

OBJECTIVES

Several previous studies have shown that malignant progression in Barrett's metaplasia (BM) occurs even in patients treated with fundoplication or acid suppression therapy (AST). The aim of this study was to test the hypothesis that AST may not alter malignant progression in BM if key genes involved in DNA repair and cell cycle control, particularly p53, are defective.

METHODS

Initial and follow-up biopsies from 21 patients with BM treated with AST and observed for 1-13 yr were entered in the study. All biopsies were graded for dysplasia and evaluated for p53 protein accumulation and oxidative DNA damage by immunohiostochemistry, using antibodies to p53 and to 8-hydroxydeoxyguanosine, respectively. DNA ploidy was determined using image analysis. Statistical analysis was performed using Kaplan-Meier curves, log rank test, and multivariate regression.

RESULTS

Patients with p53 positive initial biopsies were more likely to have progression in dysplasia grade (p = 0.022) and DNA ploidy status (p = 0.023) than those with p53 negative biopsies. In eight patients AST resulted in significant reduction in oxidative DNA damage in the five patients with p53-negative initial biopsies, but not the three with p53 positive ones (p = 0.0007).

CONCLUSIONS

We conclude that failure of AST to alter malignant progression in BM may be due, at least in part, to defects in DNA repair and cell cycle control resulting from p53 gene mutation, present before AST treatment. Although AST may be effective in preventing further DNA damage, it is unlikely to alter progression in genetically unstable cells.

Estrogen receptor-beta is expressed in Barrett's metaplasia and associated adenocarcinoma of the esophagus

Estrogen receptor-beta (ER-B) has been identified in benign and malignant tissues of a variety of human organs including the colon. In breast carcinoma, ER-B was found to be a significant predictor of response to adjuvant hormonal therapy with tamoxifen. The aim of the present study was to determine whether esophageal adenocarcinoma, and its precursosr, Barrett's metaplasia, express ER-B. Sections of formalin-fixed and paraffin-embedded tissue from 31 esophagectomy specimens were immunostained for ER-B using the immunoperoxidase technique, and the percent of positive cells in areas of Barrett's metaplasia negative for dysplasia (ND), low-grade dysplasia (LGD), high-grade dysplasia (HGD) and adecocarcinoma, (CA) were recorded. Nuclear ER-B staining in >50% of the cells was seen in all 23 CA (100%), 10 out of 11 (91%) HGD, 8 out of 11 (83%) LGD and in 10 of 15 (66.6%) ND. It is concluded that all adenocarcinomas of the esophagus and most precursor lesions, Barrett's Metaplasia (BM) with or without dysplasia, express ER-B in a significantly high percentage of the cells. These findings raise the possibility that esophageal adenocarcinomas may benefit from treatment and/or chemoprevention with antiestrogens, such as tamoxifen.

Is immunostaining for Helicobacter pylori superior to the special stain thiazine in detecting small numbers of H. pylori in gastric biopsies?

Helicobacter pylori is implicated in the pathogenesis of gastritis and duodenal ulcers, gastric lymphoma of the mucosa-associated lymphoid tissue (MALT) type, and gastric adenocarcinoma. Eradication of H. pylori with antibiotic therapy therefore is essential, not only for the successful treatment of active gastritis, but also for the treatment and prevention of the MALT lymphoma. It has been suggested recently that immunostaining for H. pylori is more sensitive than special stains for the detection of the organism in the gastric biopsies after triple therapy. Fifty-five endoscopic mucosal biopsies from 38 patients, including 18 treated with H. pylori eradication therapy, were selected for immunostaining because they were either negative or contained rare H. pylori organisms by thiazine stain. Formalin-fixed, paraffin-embedded tissue sections were immunostained for H. pylori using a polyclonal antibody using standard immunoperoxidase technique. The results were compared with those obtained with the thiazine stain. Detection of H. pylori by immunostaining was easier and less time-consuming than by thiazine stain. There was complete agreement between immunostaining and thiazine stain in 48 (87%) cases. Of the 7 discordant cases, 3 (42%) were positive for H. pylori with thiazine only and 4 (48%) with immunostaining only. Given the nature of the selection of the study sample (absent to rare by thiazine stain), the discordance most likely represents a sampling error. The authors concluded that immunostaining for H. pylori did not appear to be more sensitive than special stains. Three cases with bacterial clumps were diagnosed previously as positive for H. pylori, but identified correctly as negative using both staining methods. Pathologists, however, should balance the added cost to patients of immunostaining against the time saved by the easier screening of the immunostained slides and the possibility of false positive results when special stains are interpreted by inexperienced pathologists.

Diagnosing primary and metastatic renal cell carcinoma: the use of the monoclonal antibody 'Renal Cell Carcinoma Marker'

The diagnosis of primary or metastatic renal cell carcinoma (RCC) can be difficult, especially in small biopsies, because of the wide variety of histologic appearances and clinical presentations that RCC can assume. An immunomarker specific for RCC is currently not available. We tested the relevant diagnostic use of the Renal Cell Carcinoma Marker (RCC Ma), a monoclonal antibody, against a normal human proximal tubular brush border antigen. Immunostaining using RCC Ma and the avidin-biotin-peroxidase complex technique was performed on archival tissues from primary and metastatic tumors of renal or nonrenal origin. A total of 122 of 153 primary RCCs (79.7%) were positive [clear cell (84%), papillary (96%), chromophobe (45%), sarcomatoid (25%), and collecting duct (0%)], with > or =10% of tumor cells stained in 93% of cases. None of the 64 primary renal tumors other than RCC, including 15 oncocytomas, was positive. Fifteen of 146 (10.2%) nonrenal primary tumors were positive (5 of 17 breast tumors, 8 of 8 parathyroid adenomas, and 2 of 7 embryonal carcinomas). Forty-two of 63 (67%) metastatic RCCs were positive with > or =10% of cells being stained in 83% of them. Two of 108 (2%) metastases from tumors other than RCCs were positive, both of which were metastatic breast carcinomas; however, only 10% (2 of 19) of metastatic breast carcinomas were positive. RCC Ma is an excellent marker for primary RCC, which should facilitate its diagnosis in a small biopsy. Although RCC Ma remains highly specific (98%) for metastatic RCC, a negative result may not rule out metastatic RCC because of a rather low sensitivity and a focal staining pattern in some of the positive cases. RCC Ma may also facilitate the differential diagnosis between oncocytoma and other types of RCC when they are composed mostly of eosinophilic cells.

Morphometric assessment of gastric antral atrophy: comparison with visual evaluation

AIMS

As part of a multinational effort to reach a consensus in the definition and evaluation of atrophic gastritis, we applied morphometric techniques to 22 antral biopsy specimens examined visually by 12 experienced gastrointestinal pathologists.

METHODS AND RESULTS

Atrophy was defined as loss of glands. Each pathologist graded atrophy with both non-standardized and standardized approaches. Discriminant function analyses of morphometric measurements were conducted to validate and grade atrophy. Kappa statistics were used to compare the performance of each pathologist against the group mode and against the discriminant functions' grading of atrophy. Three morphometric indexes showed significant differences among categories of atrophy utilizing non-standardized as well as standardized visual atrophy grades: (i) the ratio of glandular length to total mucosal thickness; (ii) the proportion of the secretory compartment area occupied by glands; and (iii) the number of glandular cross sections per 40x microscopic field. The discriminant function analyses verified all cases classified visually as either non-atrophic, or moderately/severely atrophic; it verified as mildly atrophic 40% of the cases classified visually as mildly atrophic; and classified the remaining 60% as moderately or severely atrophic. The kappa statistics were good or excellent for the majority of pathologists.

CONCLUSIONS

The evaluation of antral atrophy, simply defined as loss of glands, can be reliable and reproducible. The visual grading of atrophy as absent, moderate and severe is entirely consistent with objective morphometric observations.

Altered gastrin regulation in mice infected with Helicobacter felis

Altered gastrin expression associated with Helicobacter pylori infection may contribute to the pathogenesis of peptic ulcer disease or gastric cancer in man, but gastrin has not been investigated in a murine model of Helicobacter infection. C57BL/6 mice were inoculated with Helicobacter felis and examined after 4-21 weeks for G and D cell numbers, antral gastrin and somatostatin mRNA, and luminal pH. In H. felis-infected mice, gastrin mRNA declined at four and six weeks after infection to 57% and 23%, respectively, of uninfected control values. Concurrently, somatostatin mRNA showed no change at four weeks and a modest 25% decrease at six weeks after infection. Similar reductions were noted in G and D cell numbers, resulting in a decrease in the G/D cell ratio after mice were infected with H. felis. Infected animals also showed a loss of parietal and chief cells, and an increased gastric pH. H. felis infection in C57BL/6 mice leads to an early suppression of G cell number and gastrin mRNA. These changes precede an alteration in somatostatin cell number and mRNA and, coupled with reductions in parietal and chief cells, may contribute both to severe impairment of gastric acid output and the potential for carcinogenic processes.

Sustained increase in gastric antral epithelial cell proliferation despite cure of Helicobacter pylori infection

OBJECTIVE

Studies of the effect of Helicobacter pylori treatment on gastric mucosa proliferation have yielded inconsistent results. We compared gastric mucosa cell proliferation posttherapy and in uninfected controls.

METHODS

Biopsies were obtained from patients with H. pylori infection before treatment and at intervals for up to 33 months. Epithelial cell proliferation was determined using Ki-67 immunostaining. The labeling index (LI) is the proportion of positively labeled cells with respect to the total number of cells. The proliferative index was calculated by multiplying the labeling index (LI) and the proliferation zone PZ (PZ = length of the area between the uppermost and lowest labeled cells).

RESULTS

The study included 27 patients with H. pylori gastritis and 35 controls. Epithelial cell proliferation (LI) was greater with H. pylori infection than without in both the antrum and corpus (65+/-5 vs 91+/-8 in the antrum and 44+/-4 vs 72+/-8 in the corpus, for uninfected controls vs H. pylori gastritis, respectively) (p = 0.0001). In the antrum there was no significant decrease in epithelial cell proliferation after cure of the H. pylori infection despite follow-up for >2 yr (labeling index = 83+/-10). In contrast, epithelial cell proliferation decreased in the corpus and became similar to that in controls after 7-13 months.

CONCLUSIONS

Patients with H. pylori infection have sustained high epithelial cell proliferation in the antrum compared to that in uninfected subjects. A continued increase in proliferation in the antrum after cure of H. pylori infection suggests continuing damage.

Decreased expression of Fas (CD95/APO1) associated with goblet cell metaplasia in Barrett's esophagus

Fas ligand (FasL) has been shown to induce apoptosis in cells expressing its receptor Fas. We have recently shown that Fas ligand is overexpressed in all cases of Barrett's metaplasia (BM) with dysplasia and esophageal adenocarcinomas, and in a few cases of BM negative with dysplasia. The aim of this work was to determine the status of Fas expression in BM with and without dysplasia or carcinoma. Formalin-fixed and paraffin-embedded tissue sections from esophageal biopsies and esophagectomy specimens with BM, with and without dysplasia and carcinoma, were immunostained for Fas and FasL using the immunoperoxidase technique. The percentage of positive cells in each case was evaluated and compared with the degree of dysplasia. When Fas expression was assessed in glands with goblet cell metaplasia, Fas immunoreactivity was either undetected or present in less than 10% of the cells in 85% of the cases, and only 1 (4%) of the 28 cases examined showed Fas immunoreactivity in more than 25% of the cells. When we compared Fas expression in goblet cell-containing glands with glands of gastric cardia phenotype, we found that in the 26 cases of BM with or without dysplasia Fas was completely undetectable in goblet cell-containing glands in 15 (58%) of the cases but was undetectable in only 3 (12%) of the glands with gastric cardia phenotype (P = .002). Fas is usually undetectable or is expressed at a low level in BM with or without dysplasia or carcinoma. Fas expression in goblet cell-containing glands is less frequent than in glands with gastric cardia phenotype in the same specimens. BM with dysplasia or carcinoma overexpress FasL, so decreased Fas expression may protect BM with dysplasia and carcinoma from self-destruction while allowing them to evade immune surveillance.

Relationship between dysplasia, p53 protein accumulation, DNA ploidy, and Glut1 overexpression in Barrett metaplasia

BACKGROUND

There is a need for molecular markers of malignant progression in Barrett metaplasia (BM). The aim of this study is to determine the relationship between dysplasia, p53 protein accumulation, DNA ploidy, and Glut1 in BM.

METHODS

Sections of esophageal biopsy specimens from 120 patients with BM were evaluated for dysplasia, p53 protein, and Glut1 expression by immunohistochemistry, and DNA ploidy by Feulgen stain and image analysis. In cases with diploid DNA histograms, the percentage cells in the G0G1 and G2M phases of the cell cycle were determined.

RESULTS

Of 108 diploid cases 19 (28%) of 69 cases with G0G1 > or = 90% or G2M > or = 8.33% were p53-positive, in contrast to only 1 (3%) of 39 cases with lower G0G1 or G2M (P = 0.0008). Of 32 p53-positive cases 11 (32%) were aneuploid, in contrast to none (0%) of 88 p53-negative cases (P < 0.0001). Ten (91%) of 11 aneuploid cases were high-grade dysplasial adenocarcinoma (HGD/CA), compared with only 1 (1%) of 109 diploid cases (P < 0.0001). Five (45%) of 11 cases with HGD/CA were Glut1-positive, in contrast to none (0%) of 109 cases without HGD/CA (P < 0.0001).

CONCLUSIONS

Our data strongly suggest that in BM, after oxidative DNA damage, as a result of gastroesophageal reflux, there is an increase in the percentage of cells in the G0G1 or G2M phases of the cell cycle to enable repair of damaged DNA; in some of these cases this is followed sequentially by p53 gene mutation and protein accumulation, DNA aneuploidy, HGD, and CA with or without Glut1 overexpression. These events can be detected in routinely processed biopsy samples.

Pheochromocytoma associated with neuroendocrine carcinoma. A new type of composite pheochromocytoma

The coexistence of pheochromocytoma and other tumor types in a single adrenal gland has been rarely documented. This type of pheochromocytoma is designated "composite" or "mixed," depending on whether the pheochromocytoma and the nonpheochromocytoma components show the same embryologic origin. The nonpheochromocytoma components reported in the composite pheochromocytoma include ganglioneuroma, ganglioneuroblastoma, neuroblastoma, and malignant schwannoma. The components found in the mixed pheochromocytoma include adrenal cortical neoplasms and spindle cell sarcoma. We report a unique case of composite pheochromocytoma in which the nonpheochromocytoma element is a neuroendocrine carcinoma. The histologic and the immunohistochemical profiles of the 2 distinct components of this tumor were typical for those of pheochromocytoma and neuroendocrine carcinoma. This dual differentiation was also supported by ultrastructural findings. This case not only broadens the morphologic spectrum of composite pheochromocytoma but also provides some additional insight into the histogenesis of this rare but fascinating type of tumor.

Helicobacter heilmannii gastritis: association with acid peptic diseases and comparison with Helicobacter pylori gastritis

We analyzed 2 antral and 1 corpus full-thickness random endoscopic gastric mucosal samples obtained from 946 patients with duodenal ulcers (6077 biopsies) and from 281 patients with nonsteroidal anti-inflammatory drug-associated gastric ulcers (1794 biopsies). We stained tissue sections with hematoxylin and eosin and Warthin-Starry silver stain and immunostained them with polyclonal antibodies against Helicobacter pylori. Hematoxylin- and eosin-stained sections from 6 patients with Helicobacter heilmannii (18 biopsies) and 23 randomly selected patients with H. pylori (68 biopsies) were evaluated and semiquantitated for the presence of acute inflammation, chronic inflammation, glandular atrophy, intestinal metaplasia, H. pylori, H. heilmannii, lymphoid follicles, or vasodilatation. Additional specimens were obtained for H. pylori culture, a CLO test, and serologic examination. H. heilmannii was detected in 6 (0.49%) of 1227 patients (14 [0.18%] of 7871 biopsies). Of these, 4 (0.42%) of 946 were patients with duodenal ulcers (9 [0.15%] of 6077 biopsies), and 2 (0.71%) of 281 were patients with nonsteroidal anti-inflammatory drug-associated gastric ulcers (5 [0.28%] of 1794 biopsies). We found H. heilmannii with hematoxylin and eosin stain, Warthin-Starry stain, and immunoperoxidase stain for H. pylori. Culture for H. pylori was negative in the four patients with duodenal ulcers. The CLO and serologic tests were positive in three of five and five of five patients, respectively. Our results indicate that H. heilmannii, like H. pylori, is associated with peptic ulcer disease (both active and inactive gastritis) and that it preferentially colonizes the gastric antrum. The severity of the H. heilmannii-associated gastritis is less intense and lymphoid aggregates are less common than in H. pylori-associated gastritis. Morphologic detection seems to be the method of choice for detecting H. heilmanni. Immunoperoxidase stain specific for H. pylori also stains H. heilmannii, indicating cross-reacting antigenic epitopes between H. heilmannii and H. pylori.

Attenuation of hydrophobic phospholipid barrier is an early event in Helicobacter felis-induced gastritis in mice

Helicobacter pylori infection has been linked to the development of gastritis which can then progress to a number of disease entities including peptic ulcer disease and gastric cancer. Since the pathogenic mechanism by which the bacteria causes gastritis is unresolved, we employed a model system, the H. felis-infected mouse to investigate the temporal relationship between bacterially-induced alterations in the hydrophobic phospholipid barrier of the stomach and the development of gastritis. In the present study, C57BL/6 mice were inoculated with 10(9) CFU of H. felis and the changes in gastric wet weight, histology, surface hydrophobicity, phospholipid/phosphatidylcholine concentration, phospholipase A2 activity, and the pH of collected gastric juice were measured 0.5-2 months postinoculation. In related experiments, we investigated the effects of treating H. felis infected mice with antibiotic/ bismuth therapy on the above gastric properties. It was determined that both gastric surface hydrophobicity and phospholipid composition were significantly attenuated as early as 2-4 weeks postinfection, preceding signs of mucosal inflammation and glandular atrophy as indicated by increases in gastric wet weight, pH and a disappearance in parietal cells. These early H. felis-induced changes in gastric surface hydrophobicity and phospholipid concentration were reversed by antibiotic/bismuth therapy. Based on these results we conclude that H. felis infection induces an early transformation of the stomach from a hydrophobic to an acid-sensitive hydrophilic state that may trigger the subsequent development of gastritis.

Metastatic breast disease 40 years after the initial diagnosis

This is the case of a patient with metastatic disease diagnosed 40 years after a radical mastectomy which was followed by radiation treatment for breast cancer. The patient had nonspecific symptoms for 3 years, and a lymph node biopsy revealed the underlying cause to be recurrent breast cancer. Excision of the largest metastases combined with chemotherapy resulted in a further 3-year remission.

Chronic obstructive uropathy in severe combined immunodeficient (SCID) mice: lymphocyte infiltration is not required for progressive tubulointerstitial injury

Progressive renal injury in humans and experimental animal models is characterized by tubular atrophy, infiltration of mononuclear inflammatory cells, and interstitial fibrosis. Permanent unilateral ureter ligation represents a reproducible model for investigating mechanisms of progressive kidney injury, and in the rat is characterized by tubular epithelial cell proliferation followed by apoptosis and progressive infiltration of monocytes and lymphocytes. Nevertheless, whether monocytes or lymphocytes play a dominant role in causing tubulointerstitial damage remains to be elucidated. In the current study, a model of chronic obstructive uropathy in the mouse is established and the role of lymphocyte infiltration in the evolution of the tubule and interstitial alterations is investigated. Permanent ligation of the left ureter in wild-type (C3H/HeJ) mice resulted in progressive atrophy of tubules and interstitial fibrosis compared with the contralateral kidney over a 30-d period. Immunoperoxidase studies on frozen sections taken from kidneys at 0, 3, 10, 20, and 30 d after ureter ligation showed that the tubulointerstitial injury was accompanied by a marked and progressive increase in interstitial macrophages and T lymphocytes, with no appreciable increase in B lymphocytes. No increase in inflammatory cells was detected in contralateral kidneys over the same time frame. The significance of T lymphocyte infiltration was examined by comparing the degree of tubular atrophy and interstitial fibrosis and the nature and quantity of the inflammatory infiltrate in wild-type mice and C3HSMn.C-Scid/J (SCID) mice subjected to permanent left ureter ligation. SCID mice have genetic defects in immunoglobulin and T cell receptor gene rearrangements and are devoid of circulating mature B and T lymphocytes. Wild-type and SCID mice developed tubular atrophy and interstitial volume expansion in the ligated kidney to the same degree and at the same rate. SCID mice developed a prominent and marked monocyte/macrophage infiltrate in the ligated kidney, which was essentially equal to that in wild-type mice. In contrast, consistent with the known absence of mature lymphocytes in SCID mice, there was essentially no T lymphocyte infiltration into the ligated kidney of SCID mice. These results demonstrate the effective establishment of the model of maintained unilateral ureter ligation in mice, which is readily applicable to genetic mutant strains thus allowing for specific investigation of the role of individual components of the inflammatory response in progressive tubulointerstitial injury. These studies further demonstrate that lymphocyte infiltration is not required for progressive tubular atrophy and increased interstitial fibrosis after maintained unilateral ureter ligation.

Immunohistochemical detection of Glut3 in human tumors and normal tissues

Malignant cells have been shown to utilize more glucose than normal cells in vitro and in vivo. Glut3 is a member of the facilitative glucose transporters family of transmembrane proteins, and its mRNA levels has been found to be elevated in human cancers, indicating that it may play a role in glucose uptake by cancer cells. Localization and extent of expression of Glut3 protein in normal and malignant human tissues is still largely unknown. We studied Glut3 expression in a series of 325 benign and malignant human tissues using standard immunoperoxidase technique. Of the normal tissues tested, Glut3 immunoreactivity was detected only in normal testis and placenta. Twelve of 14 (86%) testicular, 3 of 22 (16%) ovarian, 2 of 8 (25%) gastric, and 11 of 41 (27%) non-small cell lung carcinomas were positive for Glut3. Other carcinomas, including those of the breast and colon, were negative. Only in Glut3-positive testicular carcinomas were most tumor cells Glut3-positive. We conclude that a) Glut3 has a limited expression in normal and malignant human tissues, as determined by immunohistochemical staining, b) Glut3 may play a role in glucose uptake in a subset of carcinomas of the lung stomach and ovary, and, therefore, these tumors may have a distinct clinical behavior, and c) Glut3 may be an attractive target for monoclonal therapy or imaging of testicular germ cell tumors.

Human erythrocyte glucose transporter (Glut1) is immunohistochemically detected as a late event during malignant progression in Barrett's metaplasia

We have previously demonstrated that the human erythrocyte glucose transporter (Glut1) is expressed in adenocarcinoma arising in Barrett's metaplasia (BM). We have also shown that Glut1 is expressed as a late event during colorectal carcinogenesis. The aim of this work was to determine the chronology of Glut1 expression during the neoplastic progression in Barrett's metaplasia. Formalin-fixed, paraffin-embedded tissue sections of 251 biopsies from 97 patients with BM were immunostained with the anti-Glut1 antibody MYM, after microwave-aided antigen retrieval, using the standard avidin-biotin complex immunoperoxidase technique. Dysplasia was graded as negative (ND), low grade (LGD)/indefinite or high grade (HGD). None of the 181 biopsies with ND (0%) or 51 biopsies with LGD (0%) showed Glut1 immunoreactivity. More importantly, although 0 of 6 biopsies with HGD (0%) expressed Glut1, 9 of 13 biopsies with adenocarcinoma (69%) were Glut1 positive (P = 0.0108, Fisher's exact test). Our results indicate that Glut1 is expressed as a late event during the neoplastic progression in BM. Prospective studies are needed to determine the clinical utility of Glut1 immunoreactivity as a marker of carcinoma in patients with BM.

p53 Protein accumulation is a specific marker of malignant potential in Barrett's metaplasia

Our aim was to determine the sensitivity and specificity of p53 accumulation as a marker of malignant potential in Barrett's metaplasia (BM). One hundred eighty biopsies from 61 patients with BM were evaluated for p53 accumulation by immunohistochemistry. Of 25 patients with LGD, 9 had p53-positive biopsies, and of these 5 (56%) developed HGD/CA, whereas 16 had p53-negative biopsies and none (0%) developed HGD/CA after similar follow-up times (P = 0.0108). As a marker of malignant potential in BM, p53 accumulation has a sensitivity of 100%, specificity of 93%, and a predictive value of a positive test of 0.56, compared to sensitivity of 100%, specificity of 64%, and predictive value of a positive test of 0.2 for a histologic diagnosis of LGD. We conclude that: (1) p53 accumulation is more specific and has better predictive value for subsequent development of HGD/CA than histologic diagnosis of LGD. (2) Patients with LGD and p53-positive biopsies are more likely to develop HGD/CA; therefore, they should be followed up more closely than those with LGD and p53-negative biopsies.

Transforming growth factor alpha (TGF-alpha) expression in biopsies of colorectal carcinoma is a significant prognostic indicator

BACKGROUND

Predicting the outcome of patients with colorectal adenocarcinoma (CRCA) prior to surgery would be valuable in selecting high-risk individuals who may benefit from pre-operative adjuvant therapy. The aim of this study is to determine whether the expression of TGF-alpha in preoperative biopsies of patients with CRCA constitutes a significant prognostic indicator.

METHODS

We studied the expression of TGF-alpha in preoperative biopsies of 106 patients with CRCA, who had at least 5 years follow-up, using an anti-TGF-alpha monoclonal antibody and utilizing the ABC immunoperoxidase technique. For survival analysis, we used the actuarial survival method, and the Log Rank test for statistical significance.

RESULTS

CRCAs with low TGF-alpha expression (less than 25% of the tumor cells immunoreactive for TGF-alpha) had a significantly poorer survival than those with high TGF-alpha expression (more than 25%). After excluding from analysis biopsies showing mucinous or poorly differentiated CRCA, known predictors of poor prognosis, the results remained significant (p = 0.0289).

CONCLUSION

It is concluded, therefore, that low or absent expression of TGF-alpha in pre-operative biopsies of patients with CRCA, as detected by immunohistochemistry, is a significant predictor of an unfavorable outcome.

Cell apoptosis and proliferation in experimental chronic obstructive uropathy

Cell proliferation and apoptosis in kidneys with chronic obstructive uropathy (COU) have not been adequately studied. Whether these fundamental cellular processes play any role in the pathogenesis and evolution of COU remains undetermined. Sprague-Dawley rats with COU induced by unilateral ureteral ligation were sacrificed at postoperative days 1, 6, 9, 15, 34, 43, 60, 75, and 90, and were compared with control, sham-operated rats sacrificed at days 0, 15, 43, and 90. The kidneys with ureteral ligation, the contralateral kidneys, and the control kidneys were submitted to in situ end-labeling of fragmented DNAs for the detection of apoptotic cells, and to immunostaining with many monoclonal antibodies directed against the nuclear antigens associated with cell proliferation for the detection of proliferating cells. Additional rats with COU were also submitted to BrdU labeling to detect proliferating cells. The tubular, interstitial, and glomerular cells showing either apoptosis or proliferation were separately quantitated and the obtained data were correlated with dry kidney weight, tubular diameter, glomerular surface area and interstitial volume. Apoptotic tubular cells in kidney with COU increased rapidly, reaching 30-fold that of control at day 25, which was followed by an equally rapid decrease to the control level. During the same period, both the dry kidney weight and the mean tubular diameter decreased markedly. These data suggest that apoptosis may play a significant role in tubular atrophy and renal weight loss. The rapid increase in tubular cell apoptosis was immediately preceded by a 37% gain in the dry kidney weight over the control; just before that increase, there was also an approximate 60-fold increase in the proliferation rate of tubular cells detected by immunostaining for proliferating nuclear antigen or by BrdU labeling. The significance of this intriguing temporal relationship of tubular cell apoptosis and proliferation remains to be elucidated, but it may have pathogenetic implications. In contrast to the rise and fall of the frequency of tubular cell apoptosis and proliferation, the frequency of interstitial cell apoptosis and proliferation displayed continuous increase toward the end of the experiment, with a roughly parallel increase in the interstitial damage. Apoptosis and proliferation of glomerular cells in kidneys with COU did not show any significant changes throughout the experiment. In conclusion, the obtained data suggest that tubular cell apoptosis may be pathogenetically related to the tubular atrophy and renal tissue loss in COU, and that proliferation and apoptosis of interstitial cells may play a role in the observed interstitial changes in this model. This study should provide the impetus for further exploration of the mechanisms of cell death and cell proliferation as a novel venue for understanding the pathogenesis of COU.

Overexpression of the human erythrocyte glucose transporter occurs as a late event in human colorectal carcinogenesis and is associated with an increased incidence of lymph node metastases

Energy metabolism of human colon cancer in vivo relies predominantly on glucose. Although studies have revealed increased expression of Glut1 mRNA in colon cancer, Glut1 protein (Glut1) expression in the large intestine and its significance are still unknown. The objective of this work was to determine whether Glut1 is present in human colorectal neoplasms and whether that presence is of biological significance. Formalin-fixed, paraffin-embedded tissue sections of 53 colonic adenocarcinomas, 82 adenomas, 46 hyperplastic polyps, and 38 normal colon samples were immunostained with the anti-Glut1 antibody MYM. The localization was carried out using the avidin-biotin immunoperoxidase technique. No Glut1 immunoreactivity was present in normal colonic mucosa or in hyperplastic polyps, whereas 8 (10%) of 82 adenomas showed such immunoreactivity. The frequency of Glut1 expression in adenomas increased with villous morphology and with the size of the adenoma. Forty-four (83%) of 53 colorectal adenocarcinomas expressed Glut1, and, of these, tumors in which >50% of the cancer cells expressed Glut1 had a significantly higher incidence of metastasis to the lymph nodes (P = 0.0001). It is concluded that (a) Glut1 is expressed as a late event in the carcinogenesis process in human colorectal cancer, and (b) expression of Glut1 in a high proportion of cancer cells is associated with a high incidence of lymph node metastases.

Wide expression of the human erythrocyte glucose transporter Glut1 in human cancers

Glucose uptake has been found to be increased in cancer cells. Previous work has shown increased expression of the human erythrocyte glucose transporter (Glut1) mRNA in some human cancers, indicating that Glut1 may play a significant role in glucose uptake by these tumors. The distribution of Glut1 protein in normal and malignant human tissues is still largely unknown. Using immunohistochemistry, we found that Glut1 is largely undetectable in normal epithelial tissues and benign epithelial tumors but is expressed in a significant proportion of a variety of human carcinomas. We hypothesize that Glut1 expression by human carcinomas indicates an increased glucose uptake, and probably increased utilization of energy, which may correlate with an aggressive behavior. The biological significance of Glut1 expression needs to be determined.

Role of luminal ammonia in the development of gastropathy and hypergastrinemia in the rat

BACKGROUND/AIMS

Chronic infection with Helicobacter pylori causes persistent elevations in gastric juice ammonia levels. Thus, we studied the effects of experimentally induced increases in gastric juice ammonia levels on gastric structure and function and gastrin homeostasis.

METHODS

Rats were fed either normal chow or the diet supplemented (20 g/dL) with ammonium or sodium acetate.

RESULTS

Long-term dietary ammonium loading for 2 weeks or longer resulted in a 1.5-2-fold increase in the weight and mucosal thickness of the stomach and proximal duodenum with evidence of mild gastritis and enterochromaffinlike cell hyperplasia. The ammonium-containing diet also induced a significant 2-3-fold increase in both circulating gastrin levels of fed rats and an increase in the postprandial gastrin responses over control values. Antral gastrin levels were also markedly elevated by long-term ingestion of the test diet, which was increased 3-4-fold over control values in fasted animals and less so after meal stimulation. Consistent with these findings, gastrin-specific messenger RNA was increased 2.5-3-fold in the antrum of ammonium fed rats, whereas actin-specific messenger RNA was not affected or decreased. Animals fed a diet supplemented with 20 g/dL sodium acetate sustained modest increases in mucosal thickness and serum and antral gastrin concentration, suggesting that nonspecific gastric injury and inflammation is also a factor that influences G-cell function.

CONCLUSIONS

Long-term exposure of the antral mucosa to elevated levels of ammonia in the gastric juice in the presence of gastritis, conditions similar to that occurring in subjects infected with H. pylori, seem to be causative factors in the development of G-cell hyperfunction.

Association between mucosal hyperplasia of the appendix and adenocarcinoma of the colon

Mucosal hyperplasia of the appendix is a seemingly benign change of poorly understood significance, at times found in patients with colorectal malignancy. To determine the incidence of this change and its association with colonic adenocarcinoma, we have examined the appendiceal mucosa in 122 ileocolectomy specimens gathered between 1987 and 1990, and in 273 consecutive appendectomies carried out during 1990 at The Methodist Hospital in Houston, Texas. We found that 23 out of 122 ileocolectomies (18.8%) showed mucosal hyperplasia of the appendix and, of these, 17 (77%) were associated with colorectal malignancy, predominantly of the right side. Moreover, 24 of 273 appendectomies (8.8%) exhibited the presence of mucosal hyperplasia and, of these, six (25%) also were associated with adenocarcinoma of the colon. On the basis of this significant rate of association, we feel that a concomitant colorectal carcinoma should be ruled out in patients who exhibit mucosal hyperplasia of the appendix.

Gastrointestinal neuroendocrine cell proliferations

The gastrointestinal neuroendocrine cell proliferations are comprised of a few hyperplasias and various neoplasias. The better characterized hyperplasias include G-cell hyperplasia, either primary or secondary, enterochromaffin-like (ECL)-cell hyperplasias, generally secondary to hypergastrinemia, and EC-cell hyperplasias. The neoplasias include carcinoid tumors, demonstrating low malignancy and divided into foregut, midgut, and hindgut varieties, poorly differentiated neuroendocrine carcinomas resembling their pulmonary counterparts the "oat cell" carcinomas both in histological pattern and in their highly malignant behavior mixed endo-exocrine tumors, which in turn can be divided into composite tumors formed by a population of endocrine cells and a population of exocrine cells, and amphicrine tumors formed by a uniform population of cells with a mixture of endocrine and exocrine phenotypic traits. Although some of these mixed tumors show a degree of malignancy intermediate between the classical carcinoid and an adenocarcinoma, more information must be gathered to establish firm prognostic parameters for these relatively new entities.

HAM56 antibody: a tool in the differential diagnosis between colorectal and gynecological malignancy

HAM56, a monoclonal antibody first used to identify macrophages and endothelial cells, also stains many carcinomas (except those arising in the digestive tract). This property is useful in the differentiation between primary ovarian and metastatic colonic carcinomas in the ovary, or between gynecological (ovarian and endometrial) and colonic implants and lymph node metastases. This distinction is important as the prognoses of colorectal and gynecological malignancies differ significantly. Sixteen primary ovarian carcinomas (10 with peritoneal implants and 3 with lymph node metastases), eight cases of primary colonic carcinomas (four metastatic to ovary, four with peritoneal implants, and four with lymph node metastases), and three primary endometrial carcinomas, all with metastases to the ovary, were immunostained with the HAM56 antibody using the ABC immunoperoxidase technique. Linear membranous immunostaining was considered positive, whereas staining of mucin and debris was regarded as negative. Using these parameters, 15/16 ovarian primaries, 9/10 ovarian implants, 3/3 ovarian lymph node metastases, and 3/3 endometrial primaries and their ovarian metastases were positive. Colonic primaries, their ovarian metastases, peritoneal implants, and lymph node metastases were all negative. It is concluded that the HAM56 antibody is a useful tool in the distinction between colorectal and ovarian malignancies in those cases where the routine histological appearance may be ambiguous.