Correlation of miR-195 with invasiveness and prognosis of breast cancer

Abstract

To explore the potential role of miR-195 on invasiveness and prognosis of breast cancer. The RNA in formalin-fixed paraffin embedded (FFPE) of 88 breast cancer patients with primary tumors was extracted, and miR-195 levels were quantified by quantitative real-time polymerase chain reaction (real-time PCR). The relationship of miR-195 levels and clinicopathological variables were assessed by Mann Whitney-U test. Recurrence-free survival and overall survival curves were derived from Kaplan-Meier estimates and the curves were compared by Log-rank tests. Cox regression analysis was used for multivariate analysis. All statistical tests were two-sided. The levels of miR-195 in the breast cancer with histological high grade, tumor size of T3-4, lymph nodal involvement or vessel invasion were significantly down-regulated, compared with those of patients with histological low grade (Z = -2.271, P = 0.023), tumor size of T1-2 (Z = -2.687, P = 0.007), no lymph node metastasis (Z = -1.967, P = 0.049) and vessel invasion (Z = -2.432, P = 0.015). In addition, no statistically significant difference (P > 0.05) was identified between miR-195 levels and hormone receptors status, HER-2 expression, TNM stage, tumor types, recurrence and menstrual status. When considering 2(-ΔCt) = 0.270 (median level) as cut-off value, Kaplan-Meier survival analysis indicated that patients with high miR-195 level showed a positive association towards a longer survival, either recurrence-free survival (χ(2) = 5.985, P = 0.014) or overall survival (χ(2) = 30.05, P = 0.000). In a multivariate analysis, miR-195 expression on FFPE correlated significantly with outcomes of breast cancer (HR = 0.040, 95%CI: 0.009 - 0.179, P = 0.000) and was independent of other prognostic factors. It suggests that miR-195 expression on FFPE is inversely correlated with histological high grade, bigger tumor size, lymph node involvement, vessel invasion. Furthermore, as independent prognostic factor, low miR-195 significantly contributes to poor outcomes of breast cancer.