[Overexpression of protein p53 and Barrett esophagus. A frequent and early event in the course of carcinogenesis].

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.