Value of p53 immunostaining in pancreatico-biliary brush cytology specimens

Brush cytology is routinely used in the assessment of pancreatico-biliary strictures but the technique has limited diagnostic sensitivity in malignant lesions. It has been suggested that ancillary techniques, such as the identification of p53 immunoreactivity, might improve diagnostic accuracy. p53 protein expression was examined in 143 consecutive brush cytology specimens from patients with pancreatic or bile duct strictures and correlated with conventional cytological assessment and clinicopathologic follow-up data. Sixty-three of 89 (70.8%) malignant strictures were identified cytologically while 45 cases (50.6%) were p53 immunoreactive. One case of bile duct adenoma with high-grade dysplasia was reported as consistent with adenocarcinoma cytologically and was p53 negative. There was one false-positive diagnosis with conventional cytology and, in a separate case, with p53 immunostaining. Nineteen specimens (13.3%) were considered atypical cytologically and p53 expression proved accurate in only 12 cases (four immunopositive carcinomas and eight negative benign strictures). In conclusion, p53 immunostaining proved less sensitive than conventional cytology in this series and its routine diagnostic use could not be supported.