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 ampulla of Vater which could distinguish aggressive lesions would be highly useful. The aim of this study was to evaluate the abnormal expression of p53 protein in a series of 34 ampullomas with the monoclonal antibody DO7 directed against p53 protein. Mutations of exons 5 to 8 of p53 gene were also detected by PCR followed by denaturating gel electrophoresis 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 surrounding dysplastic mucosa of p53 positive infiltrative lesions. There was no correlation between p53 immunostaining and tumor stage. Among the 19 tumors analyzed, 6 mutations were detected. Conclusion. - p53 gene mutations and p53 protein immunoreactivity are frequently present in ampullomas. Because these alterations are not correlated to tumor extension and occur at an early stage in the carcinogenesis, their detection does not appear to be contributive for diagnosis of ampullary tumors.