CREPT expression correlates with poor prognosis in patients with retroperitoneal leiomyosarcoma

Retroperitoneal leiomyosarcomas (LMSs) are rare gynecological malignancies that display poor prognosis and high mortality. Cell cycle-related and expression-elevated protein in tumor (CREPT) is an oncogene that is involved in the regulation of many cell cycle-related proteins. However, its distribution and clinical significance in retroperitoneal LMS remains poorly understood. This study assessed the histological classifications of postoperative tumor samples from 71 cases of retroperitoneal LMS that were collected at The General Hospital of the People's Liberation Army from January 1998 to December 2012. We found that more than half of the patients displayed positive expressions of CREPT, Ki-67 and PCNA via immunohistochemical analysis. The expression of CREPT correlated with histological grade (P = 0.044), and the PCNA expression level correlated with the differentiation of tumor cells and histological grade (P < 0.001 and P = 0.009, respectively). Multivariate analysis showed that survival was associated with histological grade and the expression level of CREPT (P = 0.011 and P = 0.012, respectively). Kaplan-Meier analysis showed that the patients lacking CREPT expression exhibited significantly longer overall postoperative survival (median, 60.0 months) than the patients displaying CREPT expression (median, 33.0 months), and CREPT expression correlated with distant recurrence within 5 years after surgery (P = 0.004). Western blot analyses showed that CREPT was more strongly expressed in the retroperitoneal LMS tumor tissue than in paired control tissue. Based on the above data, we concluded that CREPT displays unique immunostaining for retroperitoneal LMS tissue and can be used to supplement other currently available retroperitoneal LMS markers.