The expression of CRM1 is associated with prognosis in human osteosarcoma

The nuclear export protein chromosomal region maintenance/exportin 1/Xpo1 (CRM1) is involved in the nuclear export of proteins and messenger RNAs and, thus, mediates the subcellular distribution of important molecules. Osteosarcoma is a ubiquitous and highly aggressive malignant bone tumor. The expression of CRM1 protein in human osteosarcoma has not been reported to date. We investigated the expression of CRM1 in 57 human osteosarcoma and 5 normal cartilage tissues. Western blot investigation revealed expression of CRM1 was significantly increased in osteosarcoma compared with normal tissues. High expression of CRM1 was significantly associated with increased serum level of alkaline phosphatase (ALP, P=0.001) but did not associate with that of lactate dehydrogenase (LDH, P=0.06). In univariate analysis, a significant association between CRM1 expression and tumor size (P=0.014) as well as histological grade (P=0.003) was observed, while high CRM1 expression was not correlated with the other clinicopathological parameters. In Kaplan-Meier survival analysis, high CRM1 expression was a significant prognostic indicator for progression-free survival (P=0.016) as well as overall survival (P=0.008). Multivariate analysis demonstrated that expression of CRM1 was an independent prognostic parameter for longer overall survival (95% CI, 1.27-5.39). Additional prospective studies are required to investigate the prognostic role of high expression of CRM1.