Expression of p53 and PCNA in cholangiocarcinoma and primary sclerosing cholangitis

The aim of this study was to Identify the pattern and significance of expre ssion of p53 and PCNA in cholangiocarcinoma and primary sclerosing cholangi tis, Histological sections from 18 patients with cholangiocarcinoma (3 of t he cases were associated with primary sclerosing cholangitis), 10 patients with primary sclerosing cholangitis without cholangiocarcinoma, and 7 patie nts with cirrhosis without cholanglocarcinoma or primary sclerosing cholang itis were stained immunohistochemically for p53 and PCNA. Samples from 17 p atients with cholangiocarcinoma (94%) stained positively for p53, Among the se 17 cases, nontumorous bile duct epithelium was positive in 7 (including 3 cases with primary sclerosing cholangitis and 2 with carcinoma in situ), and were positive proliferating bile ductules in 4 cases. The single p53-ne gative cholanglocarcinoma did not show p53 positivity In either the bile du ct epithelium or the proliferating bile ductules, Bile ductal and ductular cells in all 10 patients with primary sclerosing cholangitis without cholan glocarcinoma and in the 7 controls were not reactive for p53, All 18 sample s from patients with cholangiocarcinoma (100%) were positive for PCNA prote in. Rile duct epithelium was positive for PCNA in nine cases (90%) of prima ry sclerosing cholangitis without cholangiocarcinoma and in six (85%) contr ols. Our study showed a high rate of p53 expression (94%) In cholangiocarci noma. The adjacent uninvolved bile duct epithelium was also immunoreactive for p53 In 7 of 17 patients (41%), These findings suggest an early p53 muta tion in bile ductal cells In cholangiocarcinogenesis. Expression of p53 may potentially be used to identify or screen, by bile duct brushings, cases o f primary sclerosing cholangitis suspected of harboring cholangiocarcinoma, Expression of PCNA was a universal feature in cholangiocarcinoma.