Aberrant expression of deubiquitylating enzyme USP9X predicts poor prognosis in gastric cancer

Background: Ubiquitin-specific peptidase 9, X-linked (USP9X), a member of deubiquitylating enzymes family, has recently been reported to be associated with a variety of cancer progression. While it functions as either oncogene or tumor suppressor in a context-dependent manner, the expression and role of USP9X in gastric cancer is largely unknown. Methods: Sixty-eight cases of patients with gastric cancer were enrolled in this study. The expression of USP9X and MCL1 were detected by immunohistochemistry. USP9X expression was further analyzed by Western blot. Furthermore, we analyzed the correlation between USP9X and MCL1 expression, as well as USP9X expression and clinicopathologic parameters of gastric cancer. Finally, the significance of USP9X expression in gastric cancer was analyzed by both Kaplan-Meier and Cox regression analysis. Results: USP9X expression significantly increased in gastric cancer tissues compared to matched normal tissues. Moreover, expression of USP9X was positive correlated with MCL1 expression (P = 0.006) and significant associated with lymph node metastasis (P = 0.016), distant metastasis (P = 0.001) and tumor staging (P = 0.013) in gastric cancer. Importantly, the increasing expression of USP9X in gastric cancer reduces overall survival rate and was an independent factor predicts poor prognosis in patients with gastric cancer. Conclusions: In this study, deubiquitylating enzyme USP9X was overexpressed in gastric cancer, suggesting a potential implication as an oncogene, and was significantly associated with a poorer survival. (C) 2017 Elsevier Masson SAS. All rights reserved.