OBJECTIVES AND METHODS In Barrett's oesophagus, the risk of malignancy is evaluated histologically with the presence of dysplasia. The abnormal expression of p53 protein could represent a useful new marker. The aim of this study was evaluate the abnormal expression of p53 protein in a series of 52 oesophagectomy specimens with Barrett's oesophagus, either non-dysplastic (n = 3), dysplastic (n = 8), or malignant (n = 41). The immunohistochemical study was made on deparaffinized sections with the monoclonal anti-p53 antibody DO7. RESULTS The 3 non-dysplastic cases were p53 negative; 1 case of low-grade dysplasia in 5 was positive, as were the 3 cases of high grade dysplasia and 33 of 41 cancers (80%), including 13 superficial cancers in 14 (93%) and 20 invasive cancers in 27 (74%). A common feature was the presence of rare p53 positive crypts in low grade dysplastic areas and non-dysplastic specialized mucosa that surrounded high grade dysplasia and cancers. CONCLUSIONS Our results confirm the high frequency of the abnormal expression of p53 protein in cancer developed in Barrett's oesophagus. This expression is a consequence of alterations of the TP53 gene, and has an important role in the carcinogenesis of Barrett's mucosa; it is likely to represent an early event. Prospective studies are needed to evaluate its interest in the surveillance of patients with Barrett's oesophagus.

Barrett's mucosa is a precancerous condition. The goal of endoscopic surveillance for patients with Barrett's esophagus is to grade dysplasia. The diagnosis of dysplasia is difficult. The aim of this study was to determine the observer variation in diagnosis of dysplasia. Thirty-seven biopsies selected from Barrett's mucosa reported as having dysplasia between 1987 and 1988 were reviewed by 4 pathologists. The biopsies were classified according to the method of Riddell, as no dysplasia, indefinite for dysplasia, low-grade dysplasia and high-grade dysplasia. Each pathologist reviewed the biopsies alone and then together. There was a total agreement between the 4 pathologists in 20 out of 37 biopsies (54 %). The pair-wise agreement varied between 65 and 84 %. It was 84 % when The pathologists belonged to the same institution. Of 222 double reviews made by 6 pairs of pathologists (37 biopsies x 6 pairs of pathologists), there were 58 disagreements: 19 low grade/high grade dysplasia, 2 high grade/indefinite for dysplasia, 1 high grade/no dysplasia, 18 low grade/indefinite for dysplasia, 2 low grade/no dysplasia, 16 indefinite for dysplasia/no dysplasia. At the second review when the pathologists evaluated the biopsies together, the agreement was 92 %; there were 3 biopsies on which there was total disagreement: twice between high grade and low grade dysplasia, once between low grade dysplasia, indefinite for dysplasia and no dysplasia. This retrospective study has shown that disagreement between pathologists was rarely found on the biopsies diagnosed as having high grade dysplasia, more often on those diagnosed as having low grade dysplasia or indefinite for dysplasia. Their number decreased when the biopsies were reviewed by several pathologists. We conclude that diagnosis of dysplasia must be interpreted according to definite criteria and by several pathologists.

L'œsophage de Barrett ou endobrachyœsophage fait partie des etats precancereux du tube digestif. La surveillance de patients porteurs d'un endobrachyœsophage repose sur la recherche d'une dysplasie dont le degre doit etre apprecie. Le diagnostic de dysplasie est difficile. Afin d'evaluer la reproductibilite du diagnostic de dysplasie, 37 biopsies d'endobrachyœsophage, sur lesquelles ce diagnostic avait ete porte entre 1987 et 1988, ont ete revues par 4 pathologistes. Les biopsies ont ete classees, selon les criteres de Riddell, en muqueuse non dysplasique, peut-etre dysplasique, avec dysplasie de bas grade, et avec dysplasie de haut grade

Barrett's mucosa is a precancerous condition. The goal of endoscopic surveillance for patients with Barrett's esophagus is to grade dysplasia. The diagnosis of dysplasia is difficult. The aim of this study was to determine the observer variation in diagnosis of dysplasia. Thirty-seven biopsies selected from Barrett's mucosa reported as having dysplasia between 1987 and 1988 were reviewed by 4 pathologists. The biopsies were classified according to the method of Riddell, as no dysplasia, indefinite for dysplasia, low-grade dysplasia and high-grade dysplasia. Each pathologist reviewed the biopsies alone and then together. There was a total agreement between the 4 pathologists in 20 out of 37 biopsies (54%). The pair-wise agreement varied between 65 and 84%. It was 84% when the pathologists belonged to the same institution. Of 222 double reviews made by 6 pairs of pathologists (37 biopsies x 6 pairs of pathologists), there were 58 disagreements: 19 low grade/high grade dysplasia, 2 high grade/indefinite for dysplasia, 1 high grade/no dysplasia, 18 low grade/indefinite for dysplasia, 2 low grade/no dysplasia, 16 indefinite for dysplasia/no dysplasia. At the second review when the pathologists evaluated the biopsies together, the agreement was 92%; there were 3 biopsies on which there was total disagreement: twice between high grade and low grade dysplasia, once between low grade dysplasia, indefinite for dysplasia and no dysplasia. This retrospective study has shown that disagreement between pathologists was rarely found on the biopsies diagnosed as having high grade dysplasia, more often on those diagnosed as having low grade dysplasia or indefinite for dysplasia.(ABSTRACT TRUNCATED AT 250 WORDS)