Decreased expression of tumour suppressor Bax-interacting factor-1 (Bif-1), a Bax activator, in gastric carcinomas

Aims: Evasion of apoptosis is one of the hallmarks of cancer. Bax- interacting factor-1 ( Bif-1) interacts with both Bax and Bak that are essential for the intrinsic pathway of apoptosis, and enhances apoptosis. The aim of this study was to explore whether alteration of Bif- 1 expression might be a characteristic of gastric cancer. Methods: We analysed the expression of Bif- 1 protein in 60 gastric adenocarcinomas by immunohistochemistry using a tissue microarray approach. Results: In normal gastric mucosal cells, surface and glandular epithelial cells strongly expressed Bif- 1. While Bif- 1 expression was detected in 24 cases ( 40%) of the gastric carcinomas, there was no Bif- 1 immunostaining in the remaining 36 cancers. Even in the 24 cases with positive Bif-1 immunostainings, 10 cancers showed decreased intensity of immunostaining compared with the normal mucosal epithelial cells. Conclusion: The decreased expression of Bif- 1 in malignant gastric epithelial cells compared with the normal mucosal cells suggests that loss of Bif- 1 expression may play a role in gastric tumorigenesis, possibly by inhibiting the apoptosis mediated by Bif- 1.