P53 GENE-MUTATIONS AND ABNORMAL EXPRESSION OF P53 PROTEIN IN TUMORS OF THE AMPULLA OF VATER

Objectives and methods. - New prognostic markers for tumors of the amp ulla of Vater which could distinguish aggressive lesions would be high ly useful. The aim of this study was to evaluate the abnormal expressi on of p53 protein in a series of 34 ampullomas with the monoclonal ant ibody DO7 directed against p53 protein. Mutations of exons 5 to 8 of p 53 gene were also detected by PCR followed by denaturating gel electro phoresis and sequencing. Results. - One of 5 adenomas (20 %) and 16 of 29 adenocarcinomas (55 %) were p53 positive by immunohistochemistry. A constant feature was the presence of p53 positive glands in the surr ounding dysplastic mucosa of p53 positive infiltrative lesions. There was no correlation between p53 immunostaining and tumor stage. Among t he 19 tumors analyzed, 6 mutations were detected. Conclusion. - p53 ge ne mutations and p53 protein immunoreactivity are frequently present i n ampullomas. Because these alterations are not correlated to tumor ex tension and occur at an early stage in the carcinogenesis, their detec tion does not appear to be contributive for diagnosis of ampullary tum ors.