p53 but not bcl-2 is expressed by most cholangiocarcinomas: a study of 28 cases

To examine the frequency and pattern of expression of p53 and bcl-2 in archival material from patients with cholangiocarcinomas and to evaluate their respective roles in its pathogenesis, diagnosis and prognosis.

Twenty-eight surgical cases of cholangiocarcinomas diagnosed at St James's University Hospital and 16 control cases were immunostained with monoclonal antibodies to p53 and bcl-2 using streptavidin-biotin complex method. Pressure cooker was used for antigen retrieval. Of the cholangiocarcinomas, 85.7% (24/28) overexpressed p53. The intensity of staining in these cases varied from 1+ in 2, 2+ in 10 and 3+ in 12 cases. None of the 28 tumours expressed bcl-2. The well differentiated nature of the tumour made assessment of dysplasia difficult, however, where present it did not express p53 or bcl-2. The bile duct epithelium adjacent to the tumour and in the control cases did not show any significant nuclear staining for either antigen.

Overexpression of p53 appears to play an important role as a late event in the pathogenesis of cholangiocarcinomas, while we found no evidence of bcl-2 overexpression. The expression of p53 in 86% of the invasive tumours, as compared to its lack in the adjacent normal bile duct epithelium, makes it potentially useful in the diagnostic histopathology of these cases.