Argonaute 2 is up-regulated in tissues of urothelial carcinoma of bladder

Argonaute 2 proteins (Ago2) have been demonstrated to be widely expressed and involved in post-transcriptional gene silencing and play key roles in carcinogenesis. However, its expression profile and prognostic value in urothelial carcinoma of the bladder (UCB) have not been investigated. Methods: Real-time quantitative PCR (qRT-PCR) and Western blot were used to explore Ago2 expression in UCBs and normal bladder tissues. Moreover immunohistochemistry (ICH) was used to detect the expression of Ago2 in UCBs. Spearman's rank correlation, Kaplan-Meier plots and Cox proportional hazards regression model were used to analyze the data. Results: Up-regulated expression of Ago2 mRNA and protein was observed in the majority of UCBs by qRT-PCR and Western blot when compared with their paired normal bladder tissues. Clinic pathological analysis was showed a significant correlation existed between the higher expression of Ago2 protein with the Histological grade, lymph node metastasis and Distant metastasis (P<0.05); Survival analysis by Kaplan-Meier survival curve and log-rank test demonstrated that elevated Ago2 expression in cancer tissue predicted poorer overall survival (OS) compared with group in lower expression (62.2% VS 86.3%, P<0.05). Notably, multivariate analyses by Cox's proportional hazard model revealed that expression of Ago2 was an independent prognostic factor in UCB. Conclusions: These results suggest that the aberrant expression of Ago2 in human UCB is possibly involved with tumorigenesis and development, and the Ago2 protein could act as a potential biomarker for prognosis assessment of bladder cancer. Further studies on the cellular functions of Ago2 need to address these issues.