Prognostic significance of Aurora-A expression in human bladder cancer

Aurora-A is an oncogenic serine/threonine kinase, which plays important roles in tumorigenesis, development and chemoresistance of human cancers. The aim of the study was to detect the expression of Aurora-A gene in bladder cancer tissues and analyze its association with prognosis of bladder cancer patients. RT-PCR was performed to detect the expression of Aurora-A mRNA in 20 cases of bladder cancer and corresponding non-tumor tissue samples. Immunohistochemistry was performed to detect the localization of Aurora-A protein in 96 cases of bladder cancer tissue samples. Associations between Aurora-A protein expression and clinico-pathological factors or survival of bladder cancer patients were statistically analyzed. It was found that the expression levels of Aurora-A mRNA in bladder cancer tissues (1.08 ± 0.24) were significantly higher than those in corresponding non-tumor tissues (0.22 ± 0.07; P < 0.01). Moreover, immunohistochemical staining results showed the localization of Aurora-A protein to be mainly located in the cytoplasm of bladder cancer cells. High levels of Aurora-A protein expression were correlated with pathological stage (P = 0.007), lymph node metastasis (P = 0.014) and venous invasion (P = 0.008), but not with other factors including age, gender, tumor grade and recurrence of superficial cancer. Patients with high expression levels of Aurora-A protein showed lower disease-free and overall survival rates than those with low expression levels (P = 0.0072 and 0.0009, respectively). Univariate and multivariate analysis of prognostic factors in bladder cancer patients indicated that Aurora-A expression was an independent unfavorable prognostic factor (hazard ratio: 0.673; 95% confidence interval: 0.388–0.912; P < 0.001). Our study suggests that overexpression of Aurora-A gene may play an important role in the progression of bladder cancer and that Aurora-A expression is an independent factor for predicting the prognosis of bladder cancer in patients.