Decreased expression of Bax-interacting factor-1 (Bif-1) in invasive urinary bladder and gallbladder cancers.
OBJECTIVE
Mounting evidence indicates that deregulation of apoptosis is involved in the mechanisms of cancer development. Bax-interacting factor-1 (Bif-1) interacts with both Bax and Bak that are crucial for the intrinsic apoptosis signalling. Functionally, loss of Bif-1 expression has been proven to enhance tumorigenesis. The aim of this study was to explore whether loss of Bif-1 expression occurs in urinary bladder (UB) and gallbladder (GB) cancer tissues.


METHODS
We analysed Bif-1 protein expression in 41 transitional cell carcinomas of UB and 26 GB adenocarcinomas by immunohistochemistry.


RESULTS
In both UB and GB, normal mucosal epithelial cells strongly expressed Bif-1 protein. In the UB cancers, Bif-1 expression was strongly positive in 25 cases (61.0%), but the remaining 16 cases showed no (14.6%) or markedly decreased (24.4%) Bif-1 immunostaining compared with the normal mucosal epithelial cells. Similarly, in the GB cancers, Bif-1 immunostaining was strong in 17 cases (65.4%), while the remaining nine cases showed no (15.4%) or markedly decreased (19.2%) Bif-1 immunostaining compared with the normal mucosal epithelial cells.


CONCLUSIONS
The decreased expression of Bif-1 in large fractions of both UB and GB cancers (39.0% and 34.6%, respectively) compared with their normal mucosal cells suggested that loss of Bif-1 expression might play a role in tumorigenesis in both UB and GB cancers, possibly by inhibiting apoptosis mediated by Bif-1.
Kim
Su Young
SY
Department of Pathology, College of Medicine, The Catholic University of Korea, Seoul.
Oh
Young Lyun
YL
Kim
Kyung Mee
KM
Jeong
Eun Goo
EG
Kim
Min Sung
MS
Yoo
Nam Jin
NJ
Lee
Sug Hyung
SH