OVEREXPRESSION OF P53 PROTEIN IN BARRETTS-ESOPHAGUS - A FREQUENT AND EARLY EVENT DURING CARCINOGENESIS

Objectives and methods. In Barrett's oesophagus, the risk of malignancy is evaluated histologically with the pre sence 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 developped 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.