Prognostic Significance of miR-145, NANOG, OCT4, and KLF4 in Triple-Negative Breast Cancer

Abstract

BACKGROUND: Among women, breast cancer is the leading cause of cancer-related deaths. OCT4, NANOG, and KLF4 are markers of cancer stem cells. miR-145 is a tumor suppressor in many cancers. We aimed to estimate the expression of miR-145 and cancer stem cell markers in triple-negative breast cancer (TNBC) and to investigate their correlations with clinicopathological characteristics and outcomes in these patients. METHODS: The study included 90 female patients with TNBC. Grade III represented 64.4% of cases, while Grades I and II represented 11.1% and 24.4%, respectively. Seventy-two patients (80%) had lymph node involvement. Breast tissues from malignant and adjacent control tissues were used for RNA extraction and subsequent analysis of miR-145 expression. Histopathological and immunohistochemical analyses were also performed. RESULTS: It was found that lymph node (LN)-positive tumors exhibited higher OCT4 levels compared to LN-negative tumors (P = 0.039). Additionally, tumors with extensive intraductal invasion and relapse showed lower KLF4 levels (P = 0.02 and <0.001, respectively). Downregulated miR-145 expression was associated with higher stages, relapse, and mortality (P < 0.001 for each), LN involvement (P = 0.002), and capsular invasion (P = 0.02). There were significant strong positive correlations between miR-145 and DFS (r = 0.920, P < 0.001) and OS (r = 0.813, P < 0.001). However, significant weak negative correlations were found with KLF4 (r = -0.242, P = 0.022), NANOG (r = -0.305, P = 0.009), OCT4 (r = -0.255, P = 0.014), tumor size (r = -0.247, P = 0.019), and the number of positive LNs (r = -0.481, P < 0.001). OCT4 levels showed significant positive correlations with NANOG (r = 0.328, P = 0.002) and KLF4 expression (r = 0.344, P = 0.001). Moreover, a significant positive correlation was detected between KLF4 levels and DFS (r = 0.255, P = 0.015). The log-rank test showed a significant association of KLF4 with DFS (P = 0.005). CONCLUSION: miR-145 and KLF4 are possible prognostic markers in TNBC. This was reflected by the positive correlations between miR-145 and both DFS and OS, and between KLF4 levels and DFS.