Expression and correlation of Bmi-1, AEG-1 and FHIT in bladder transitional cell carcinoma

BACKGROUND: To explore the expression and correlation of B-cell-specific Moloney murine leukemia virus insertion site 1 (Bmi-1), astrocyte elevated gene-1 (AEG-1) and fragile histidine triad (FHIT) in bladder transitional cell carcinoma (BTCC). METHODS: Forty-six tissue samples were obtained from patients diagnosed with primary bladder cancer during the first radical cystectomy between June 2010 and January 2014. The expression of Bmi-1, AEG-1 and FHIT in normal tissues and BTCC tissues in different histological cell types, clinical pathological stages and lymph node metastatic status were evaluated by quantitative real time polymerase chain reaction (qRT-PCR), Western blot and immunohistochemistry. Relationships between Bmi-1, AEG-1 and FHIT were determined using linear correlation coefficient. RESULTS: The results of qRT-PCR showed the relative expression of Bmi-1 and AEG-1 were higher and the expression of FHIT was lower in BTCC tissues than those in normal tissues, whether in different histological cell types, clinical pathological stages or lymph node metastatic status (P<0.05). Similarly, the up-regulated expression of Bmi-1 and AEG-1 and down-regulated expression of FHIT in BTCC tissues were observed by the Western blot and immunohistochemistry compared with normal tissues (P<0.05). Linear correlation analysis showed the expression of Bmi-1 was positively correlated with AEG-1 (r>0.90, P<0.01), which was negatively correlated with the expression of FHIT, respectively (r=−0.84, P<0.05). CONCLUSIONS: The study demonstrated the up-regulated expression of Bmi-1 and AEG-1 and the down-regulated expression of FHIT in BTCC tissues. The interaction of Bmi-1, AEG-1 and FHIT may involve in the tumorigenesis, progression and invasion of BTCC through NF-κB/MMP-9 pathway.