Prognostic significance of mammalian sterile 20-like kinase 1 in breast cancer.

Mammalian sterile 20-like kinase 1 (Mst1) has been proved in the process of apoptosis and tumor suppression. The aim of the study was to investigate the expression of Mst1 in breast cancer and to evaluate its prognostic significance. The expression of Mst1 was examined in 110 breast cancer patients by immunohistochemistry, in which 80 (72.7 %) were defined as positive for Mst1 expression. Patients with negative expression of Mst1 had poor overall survival, comparing with those with positive expression using Kaplan-Meier survival analysis (P = 0.009). Multivariate analysis using Cox proportional hazards model showed that Mst1 expression was a significant independent prognostic factor in breast cancer (P = 0.030). Our results presented the tumor suppressive role of Mst1, and confirmed Mst1 was a prognostic factor in human breast cancer.