ABSENCE OF OVER-EXPRESSION OF P53 PROTEIN IN BENIGN AND MALIGNANT PARAGANGLIOMAS

Expression of abnormally stable mutant forms of the protein encoded by the gene known as p53 is an extremely common event in human neoplasms , a fact reflecting its crucial role in the regulation of cell turnove r. Although widely investigated in a range of tumours from a variety o f sites, there do not, to our knowledge, appear to have been any studi es of its expression in paragangliomas. Abnormal expression of p53 pro tein was absent from 15 morphologically typical adrenal (2) and extra- adrenal(13) paragangliomas, 3 were overtly malignant, when sought for using the DO-7 antibody (Dako), whilst colon adenocarcinomas known to abnormally express the protein and used as controls were consistently positive. These results suggest that the mechanism of any dysfunction of the p53 encoding gene in paragangliomas might differ from that in t umours from other sites such that its detectable overexpression does n ot result.