Cripto-1 expression and its prognostic value in human bladder cancer patients

Cripto-1 is an important embryonic gene that involved in self-renewal and maintenance of pluripotency of stem cells. Overexpression of Cripto-1 has been found to be correlated with tumorigenesis and may affect tumor recurrence and metastasis. The previous studies indicate that Cripto-1 might be a potential prognostic biomarker for several malignancies. The aim of this study is to examine Cripto-1 expression pattern and clinicopathological significance in human bladder cancer patients. We investigated Cripto-1 expression in 30 paired bladder cancer tissues and corresponding noncancerous bladder tissues using real-time quantitative RT-PCR (qRT-PCR). Moreover, Cripto-1 expression in 130 bladder cancer specimens and bladder cancer T24 and 5637 cells were analyzed using immunohistochemistry and immunofluorescence assays. The recurrence/metastasis-free survival was assessed by Kaplan-Meier method and log-rank test. Cox regression was also used for univariate and multivariate analyses of prognostic factors. The results showed that Cripto-1 expression is increased in bladder cancer tissues and is significantly associated with tumor size (P = 0.005) and tumor grade (P = 0.035). In addition, the expression level of Cripto-1 in bladder cancer was also found to be significantly associated with SRY-related HMG-box gene 2 expression (P = 0.003) and Ki-67 (P = 0.001). Compared with the patients with low Cripto-1 expression, the patients with high Cripto-1 expression had significantly poorer recurrence/metastasis-free survival (P = 0.011). Cox regression showed that Cripto-1 might be an independent prognostic factor for recurrence/metastasis-free survival (P = 0.036). Our findings suggest that high Cripto-1 expression might be involved in the development of bladder cancer and a potentially effective prognostic marker in bladder cancer patients.