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Ubiquitin-specific protease 7 expression is a prognostic factor in epithelial ovarian cancer and correlates with lymph node metastasis

Authors Ma M, Yu N

Received 7 November 2015

Accepted for publication 15 January 2016

Published 16 March 2016 Volume 2016:9 Pages 1559—1569


Checked for plagiarism Yes

Review by Single-blind

Peer reviewers approved by Dr Manfred Beleut

Peer reviewer comments 3

Editor who approved publication: Professor Daniele Santini

Ming Ma,1 Nina Yu2

1Department of Oncology, 2Department of Gynecology and Obstetrics, Linyi People’s Hospital, Linyi, People’s Republic of China

Objective: Ubiquitin-specific protease 7 (USP7) is a common target of herpesviruses and is important in the DNA damage response, which is also upregulated in several cancers, including prostate, colon, liver, and lung cancers. However, less is known about its expression in ovarian cancer tissues. The role of USP7 in epithelial ovarian cancer (EOC) has not yet been investigated.
Materials and methods: We recruited 141 patients from Linyi People’s Hospital between June 1999 and June 2013, all pathologically diagnosed with primary EOC. Their clinical data were collected, and the expression of USP7 in the tumor tissues was determined using immunohistochemistry. The correlations between USP7 expression and the clinicopathological variables of patients with EOC were assessed using Spearman’s rank correlation test. Kaplan–Meier analysis and Cox regression analysis were used to identify the prognosis value of USP7. The function of USP7 in the EOC cells was also detected in vitro.
Results: Among the 141 cases, USP7 expression was high in 59 EOC samples (41.8%), and was significantly correlated with lymphatic invasion; USP7 can act as independent prognostic indicator for the overall survival (OS) of EOC, and its high expression was associated with poor OS rate. The RNA inteference and overexpression assays indicated that USP7 can positively regulate the ovarian cell vitality and invasion process.
Conclusion: Patients with EOC expressing high level of USP7 have worse OS compared with those with low USP7 expression. USP7 may be involved in the proliferation and invasion of EOC cells, and USP7 expression can serve as an independent predictor of EOC.

Keywords: epithelial ovarian cancer, USP7, lymph node metastasis, invasion, prognosis

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