The
protein encoded by the p53 tumour suppressor gene plays an important part in the regulation of cell growth. Abnormalities of this gene represent one of the most common genetic changes in the development of human
cancers. This study investigated the expression of p53
protein in
cholangiocarcinoma arising in association with
primary sclerosing cholangitis (PSC). Of the 14 patients with
cholangiocarcinoma studied, 13 had underlying PSC. The expression of p53
protein was detected immunohistochemically in
paraffin wax embedded liver specimens, after microwave pretreatment. The expression of p53
protein was shown in the
cholangiocarcinoma tissue of 11 of 14 (78.5%) patients. In five of 10 patients, the accumulation of p53
protein highlighted the presence of neoplastic cells in biliary tissue separate from the main tumour. These cells were mainly located in the septal bile ducts or in the accessory glands, or both, but occasionally also in large portal areas at the periphery of nerves and lymphatics, and in one case in the mucosa of an extrahepatic bile duct. No p53
protein was detectable in liver tissue obtained at the time of
transplantation in 15 patients with PSC but not
cholangiocarcinoma. These results show that
cholangiocarcinoma development in PSC is commonly associated with abnormalities of p53 and that these occur at a late stage in the development of the malignant process. Staining for p53
protein could represent an additional criterion for the diagnosis of
cholangiocarcinoma development in patients with PSC.