Published in:
Open Access
01-12-2013 | Research article
Overexpression of YAP 1 contributes to progressive features and poor prognosis of human urothelial carcinoma of the bladder
Authors:
Jian-Ye Liu, Yong-Hong Li, Huan-Xin Lin, Yi-Ji Liao, Shi-Juan Mai, Zhou-Wei Liu, Zhi-Ling Zhang, Li-Juan Jiang, Jia-Xing Zhang, Hsiang-Fu Kung, Yi-Xin Zeng, Fang-Jian Zhou, Dan Xie
Published in:
BMC Cancer
|
Issue 1/2013
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Abstract
Background
Yes-associated protein 1 (YAP 1), the nuclear effector of the Hippo pathway, is a key regulator of organ size and a candidate human oncogene in multiple tumors. However, the expression dynamics of YAP 1 in urothelial carcinoma of the bladder (UCB) and its clinical/prognostic significance are unclear.
Methods
In this study, the methods of quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting and immunohistochemistry (IHC) were utilized to investigate mRNA/ protein expression of YAP 1 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 YAP 1 mRNA and protein was observed in the majority of UCBs by qRT-PCR and Western blotting, when compared with their paired normal bladder tissues. By IHC, positive expression of YAP 1 was examined in 113/213 (53.1%) of UCBs and in 6/86 (7.0%) of normal bladder specimens tissues. Positive expression of YAP 1 was correlated with poorer differentiation, higher T classification and higher N classification (P < 0.05). In univariate survival analysis, a significant association between positive expression of YAP 1 and shortened patients’ survival was found (P < 0.001). In different subsets of UCB patients, YAP 1 expression was also a prognostic indicator in patients with grade 2 (P = 0.005) or grade 3 (P = 0.046) UCB, and in patients in pT1 (P = 0.013), pT2-4 (P = 0.002), pN- (P < 0.001) or pT2-4/pN- (P = 0.004) stage. Importantly, YAP 1 expression (P = 0.003) together with pT and pN status (P< 0.05) provided significant independent prognostic parameters in multivariate analysis.
Conclusions
Our findings provide evidences that positive expression of YAP 1 in UCB may be important in the acquisition of an aggressive phenotype, and it is an independent biomarker for poor prognosis of patients with UCB.