Introduction: Breast cancer is a complex disease due to several biological Levels of genetic and epigenetic changes that ultimately alter the cellular processes including proliferation, apoptosis, angiogenesis and the acquisition of an invasive phenotype results. BIF-1 (BAX interacting factor) is a tumor suppressor gene which is involved in the regulation of mitochondrial membrane bends and containing BAR domains that mediate interaction with BAX. The aim of this study was to investigate the relative gene expression differences of BIF-1 in human breast tumor compared with normal adjacent tissues using Real-Time PCR method.
 
Materials & methods: This case-control study was implemented on 50 tumour and normal adjacent tissue samples of breast cancer patients. The patients had referred to Milad and Khatam hospitals in 2014. After collecting the samples, total RNA was extracted from tissue by TriPure RNA isolation kit. The cDNA was synthesized from extracted RNA by Revert AID First strand cDNA synthesis kit. Finally the BIF-1 gene expression was analyzed in tumor and normal adjacent tissues using SYBR green Real-Time PCR.
 
Findings: Our results indicated that BIF-1 was down regulated in 34 breast cancer patients which was statically significant (P=0.001). This lower mean of BIF-1 gene expression in tumor tissues compared with normal adjacent ones confirmed its role as a tumor suppressor gene.
 
Discussion & conclusions: Due to the significant difference in BIF-1 gene expression in breast tumor and normal tissue, this gene may candidate as a possible biomarker related to breast cancer.