Prognostic value of Musashi-1 in endometrioid adenocarcinoma.

AIMS Musashi-1, a RNA-binding protein, is suggested to be a cancer stem cell-related marker; its high level of protein expression is reported to be associated with high histological grade in some tumors. The aim of this study was to investigate the prognostic value of Musashi-1 in patients with endometrioid adenocarcinoma (EAC). METHODS We examined the Musashi-1 mRNA expression level in 35 fresh EAC tissue samples and 15 normal endometrium samples by real-time RT-PCR, and its protein expression level in 148 paraffin EAC tissue samples and 20 paraffin normal endometrium samples by immunohistochemistry. The correlation between Musashi-1 and overall survival (OS) used Cox proportional hazards regression. The prognostic accuracy of Musashi-1 compared with other clinicopathological risk factors by logistic regression. Furthermore, we examined whether Musashi-1 expression is correlated with another cancer stem cell marker CD133 by real-time RT-PCR. RESULTS Musashi-1 mRNA expression of EAC is 2.8-fold higher than that of normal endometrium (P=0.0009). Musashi-1 protein expression level is correlated with tumor stage, grade and vascular invasion. Patients with higher protein expression level of Musashi-1 are associated with poor survival rate than those with negative or low level of expression (HR=2.073, P=0.001). The area under the curve (AUC) for Musashi-1 is 0.8, which is higher than other clinicopathological factors (P=0.000). In addition, Musashi-1 mRNA expression seems to be closely correlated with CD133 expression (r=0.7167, P<0.0001). CONCLUSIONS Our results suggest high level of Musashi-1 protein expression is associated with poor survival in EAC patients, which may be an independent prognostic factor for EAC.