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

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 metabolsm of human colon cancer in vivo relies predominantly on glucose. Although studies have revealed increased expression of GIut1 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 \u3e50% 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

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

p53 protein accumulation in Barrett\u27s metaplasia, dysplasia, and carcinoma: A follow-up study

Background: There is a significant interobserver and intraobserver variation in grading dysplasia in Barrett\u27s metaplasia. New markers are needed to optimize the assessment of potential risk of cancer development in these patients. The aim of this study is to explore the use of p53 as a marker of neoplastic progression in Barrett\u27s metaplasia. Methods: Immunohistochemistry was used to study p53 protein accumulation in 114 specimens from 54 patients with Barrett\u27s metaplasia. Results: Positive staining was found in 0% of the cases negative for dysplasia, 9% of those with lowgrade dysplasia, 55% of those with high-grade dysplasia, and 87% of those with adenocarcinoma. Follow-up was available on 24 patients. Two patients who showed low-grade dysplasia and who were positive for p53 on biopsy showed high-grade dysplasia in follow-up biopsies. Of 21 patients who had biopsy specimens negative for p53, only one showed high-grade dysplasia on subsequent biopsy specimens. Conclusions: Our data support the hypothesis that p53 plays an important role in the progression of Barrett\u27s metaplasia to adenocarcinoma. The follow-up study indicates that positive immunostaining for p53 may be an objective marker of neoplastic progression in Barrett\u27s metaplasia. © 1993

Immunohistochemical detection of glut 3 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\u27s metaplasia

We have previously demonstrated that the human erythrocyte glucose transporter (Glut1) is expressed in adenocarcinoma arising in Barrett\u27s 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\u27s 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\u27s 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\u27s metaplasia

Our aim was to determine the sensitivity and specificity of p53 accumulation as a marker of malignant potential in Barrett\u27s 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

Estrogen receptor-beta is expressed in Barrett\u27s 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\u27s 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\u27s metaplasia negative for dysplasia (ND), low-grade dysplasia (LGD), high-grade dysplasia (HGD) and adecocarcinoma, (CA) were recorded. Nuclear ER-B staining in \u3e50% 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\u27s 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