title: Decreased expression of Bax-interacting factor-1 (Bif-1) in invasive urinary bladder and gallbladder cancers.
abstract: 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.
authors.affiliation: Department of Pathology, College of Medicine, The Catholic University of Korea, Seoul.
authors.forename: Su Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Young Lyun
authors.initials: YL
authors.lastname: Oh
authors.forename: Kyung Mee
authors.initials: KM
authors.lastname: Kim
authors.forename: Eun Goo
authors.initials: EG
authors.lastname: Jeong
authors.forename: Min Sung
authors.initials: MS
authors.lastname: Kim
authors.forename: Nam Jin
authors.initials: NJ
authors.lastname: Yoo
authors.forename: Sug Hyung
authors.initials: SH
authors.lastname: Lee