[Does the criterium of positivity for the immunohistochemical analysis of p53 in the confirmation of Barrett's dysplasia make any difference?].

Background: Barrett's esophagus is the most serious complication of the gastroesophageal reflux disease and presents a malignant potential. The expression of the tumoral marker p53 increases with the dysplasia-adenocarcinoma sequence.

Aims: To evaluate the p53 expression in Barrett's esophagus with or without dysplasia according to the two positive immunostaining criteria.

Materials And Methods: The material was constituted by endoscopic biopsy specimens from 42 patients with Barrett's esophagus. Section of formalin-fixed and paraffin-embedded biopsies were stained with hematoxylin-eosin, PAS-alcian blue and evaluated the p53 immunohistochemical expression. Two p53 immunostaining criteria were utilized: 1. The staining of, at least, half of the nuclei, and 2. The staining of any nucleus. The diagnosis of dysplasia was confirmed by the agreement between three pathologists.

Results: The total number of tissue specimens was 229, with an average of 5.4 specimens per patient. Dysplasia, with agreement for all pathologists examining the same set of slides, was detected in six (14.3%) cases. According to the two different p53 immunostaining criteria, the protein was detected in non-dysplastic Barrett's metaplasia, respectively, in 5 (13.9%) and 14 (38.9%) patients. Specifically in the six dysplastic cases, p53 was detected, according to the immunostaining criteria, in one (16.7%) and four (66.7%) cases, respectively.

Conclusions: In this group, p53 immunohistochemical expression, regardless of positive criteria take into account, was not useful for detecting dysplasia in Barrett's esophagus.