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

Objectives and methods. In Barrett's oesophagus, the risk of malignanc y is evaluated histologically with the pre sence of dysplasia. The abn ormal expression of p53 protein could represent a useful new marker. T he aim of this study was evaluate the abnormal expression of p53 prote in in a series of 52 oesophagectomy specimens with Barrett's oesophagu s, either non-dysplastic (n = 3), dysplastic (n = 8), or malignant (n = 41). The immunohistochemical study was made on deparaffinized sectio ns with the monoclonal anti-p53 antibody DO7. Results. - The 3 non-dys plastic cases were p53 negative; 1 case of low-grade dysplasia in 5 wa s positive, as were the 3 cases of high grade dysplasia and 33 of 41 c ancers (80 %), including 13 superficial cancers in 14 (93 %) and 20 in vasive 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. C onclusions. - Our results confirm the high frequency of the abnormal e xpression 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 i s likely to represent an early event. Prospective studies are needed t o evaluate its interest in the surveillance of patients with Barrett's oesophagus.