Background: The aim of this study is to explore the expression of beclin 1, an autophagy gene, in bladder cancer and to evaluate its clinical and prognostic significance in patients with bladder cancer.
Methods: Beclin 1 expression was examined at mRNA and protein levels by real-time quantitative polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemistry in bladder cancer tissues and adjacent normal bladder tissues. The relationship between the expression of beclin 1 and clinicopathological characteristics and prognosis was statistically analyzed.
Results: mRNA level, protein expression and immunoreactivity of beclin 1 were decreased in bladder cancer tissues compared with adjacent normal tissues. Downregulation of beclin 1 was more frequent in tumors with higher histological grades (the expression of beclin 1 was reduced by 49.0% in G1 and G2, and by 71.8% in G3, p=0.010), and was also reduced by 69.5% in the muscle invasive type and by 51.1% in the non-muscle invasive type (p=0.04). Reduced beclin 1 expression was positively associated with higher histological grade and more advanced clinical stage (p<0.05). Kaplan-Meier survival analysis revealed that patients exhibiting lower beclin 1 expression experienced a shorter survival than those with higher expression (p=0.006). Cox proportional hazards regression analysis showed that beclin 1 protein is an independent predictor of survival (p=0.005).
Conclusion: Beclin 1 has an influence on the progression of bladder cancer and might serve as a potential prognostic factor for patients with bladder cancer.