Elevated XPO6 expression as a potential prognostic biomarker for prostate cancer recurrence

Recurrence of localized prostate cancer following treatment can lead to lethal metastatic castration-resistant prostate cancer. Although numerous studies aimed at developing biomarkers for predicting recurrence of localized prostate cancer are promising, they have not yet led to useful applications. Dysregulation of exportins (XPOs, nucleocytoplasmic transporters) associated with subcellular mislocalization of proteins has been reported for various human cancers. However, most of the XPOs have not been studied in prostate cancer. In this study, we are the first to examine whether changes in expression of XPOs could be used as potential biomarkers for recurrence of localized prostate cancer. Using the oncomine database, gene expressions of 7 known XPOs by 1128 patient samples, obtained from 16 independent prostate cancer patient cohorts, were analyzed. Relatively highly elevated expression of XPO6 (compared to prostate cancer tissue) was found to be significantly associated with poor patient prognosis, in particular, with rapid recurrence in a clinical low risk group. As such, expression of XPO6 may be a potential prognostic biomarker for predicting prostate cancer recurrence.