Low expression of miR-597 is correlated with tumor stage and poor outcome in breast cancer

MicroRNAs (miRNAs) have been reported to play important roles in the progression of breast cancer (BC). In the present study, we aimed to explore the association between miR-597 expression level and prognosis of BC.

The expression levels of miR-597 were measured using quantitative Real-time polymerase chain reaction (qRT-PCR) analysis. The association between miR-597 expression and clinicopathological factors was analyzed. Differences in BC patient survival were determined using the Kaplan-Meier method and log-rank test. The prognostic value of miR-597 was further verified using the Cox proportional hazards regression model.

Our data indicated that miR-597 was lowly expressed in BC compared with adjacent non-malignant tissues (p<0.001). Low miR-597 expression was observed to be closely associated with positive lymph node metastasis (p=0.001), higher TNM stage (p = 0.003), and poorer pathological differentiation (p=0.006). Furthermore, patients with lower levels of miR-597 expression had a shorter overall survival time than patients with higher miR-597 expression levels (p=0.009). In addition, multivariate Cox proportional hazards model analysis confirmed that miR-597 was an independent prognostic indicator of overall survival (p=0.005; HR 2.273; CI 95%, 1.117-4.291).

We showed, for the first time, that decreased miR-597 expression suggested unfavorable prognosis for BC patients.