Expression of Bcl-2 and Bax in extrahepatic biliary tract carcinoma and dysplasia.
OBJECTIVE
To compare the difference of expression of Bcl-2 and Bax in extrahepatic biliary tract carcinoma and dysplasia, and to analyze the role of Bcl-2 and Bax proteins in the progression from dysplasia to carcinoma and to evaluate the correlation of Bcl-2/Bax protein expression with the biological behaviors.


METHODS
Expressions of Bcl-2 and Bax were examined immunohistochemically in 27 cases of extrahepatic biliary tract carcinomas (bile duct carcinoma: n=21, carcinoma of ampulla of Vater: n=6), and 10 cases of atypical dysplasia. Five cases of normal biliary epithelial tissues were used as controls. A semiquantitative scoring system was used to assess the Bcl-2 and Bax reactivity.


RESULTS
The expression of Bcl-2 was observed in 10 out of 27 (37.0%) invasive carcinomas, 1 out of 10 dysplasias, none out of 5 normal epithelial tissues. Bax expression rate was 74.1% (20/27) in invasive carcinoma, 30% (3/10) in dysplasia, and 40% (2/5) in normal biliary epithelium. Bcl-2 and Bax activities were more intense in carcinoma than in dysplasia, with no significant difference in Bcl-2 expression (P=0.110), and significant difference in Bax expression (P=0.038). Level of Bax expression was higher in invasive carcinoma than in dysplasia and normal tissue (P=0.012). Bcl-2 expression was correlated to Bax expression (P=0.0059). However, Bcl-2/Bax expression had no correlation with histological subtype, grade of differentiation, or level of invasion.


CONCLUSIONS
Increased Bcl-2/Bax expression from dysplasia to invasive tumors supports the view that this is the usual route for the development of extrahepatic biliary tract carcinoma. Bcl-2/Bax may be involved, at least in part, in the apoptotic activity in extrahepatic biliary carcinoma.
Li
Sheng-Mian
SM
Department of Internal Medicine, the Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, China. kyc@hbmu.edu
Yao
Shu-Kun
SK
Yamamura
Nobuyoshi
N
Nakamura
Toshitsugu
T
D017209:Apoptosis; D017734:Bile Ducts, Extrahepatic / Q000378:metabolism* / Q000473:pathology; D001661:Biliary Tract Neoplasms / Q000378:metabolism* / Q000473:pathology*; D018450:Disease Progression; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein