Expressions of p53 and inducible nitric oxide synthase in congenital choledochal cysts.

BACKGROUND: Choledochal cyst, an isolated defect unrestricted to the bile duct, is more appropriately regarded as the sentinel feature of a constellation of anomalies affecting the pancreatobiliary system. This study was to assess the relationship between the expression of inducible nitric oxide synthase (iNOS) and the p53 gene as well as the pathogenesis of choledochal cysts. METHODS: iNOS and p53 were detected by immunohistochemistry staining in 26 patients with congenital choledochal cysts. Histopathologically, hyperplasia of the mucosa of the cysts and the amylase level in the bile were also investigated. RESULTS: Patients with a high level of amylase in the bile had higher expression of iNOS than those with a low level of amylase. p53 protein was expressed neither in fusiform type nor in cystic type. The incidence of mucosal hyperplasia was significantly higher in the fusiform type than that in the cystic type. CONCLUSIONS: Higher expression of iNOS may participate in hyperplasia and carcinogenesis of the mucosa of choledochal cysts. The regurgitation of pancreatic juice into the biliary system might induce mucosal hyperplasia of the biliary tract and inflammatory reaction. In preventing regurgitation-caused hyperplasia and malignancy of the bi-liary tract, early surgery is important for children with congenital choledochal cysts.