ObjectiveTo investigate the expression of ubiquitin-specific protease 9X (USP9X) in pancreatic cancer, and to evaluate the correlation of USP9X with the survival of patients with pancreatic cancer. MethodThe expression of USP9X was detected in 55 pieces of surgically resected primary pancreatic cancer tissues and adjacent nontumorous pancreatic tissues by streptavidin-perosidase immunohistochemical method. ResultsThe rate of USP9X high expression in the 55 pieces of the primary pancreatic cancer tissues was 58.2% (32/55), which in the adjacent nontumorous pancreatic tissues was zero. The expression of USP9X was not correlated with the gender, age, tumor position, or tumor size (P > 0.05), while which was significantly correlated with the differentiation degree, lymph node metastasis, or TNM stage (P < 0.05). By using Cox proportional hazard model, the multivariable analysis revealed that the differentiation degree, lymph node metastasis, and USP9X expression were the independent risk factors. Survival of the patient with USP9X high expression was significantly shorter than that with USP9X low expression (P < 0.05), and there was the same result in the patients with stageⅡ, with lymph node negative, or intermediate differentiation degree (P < 0.05). ConclusionThe results indicate that USP9X might play an important role in the pathogenesis and prognosis of pancreatic cancer.