The dysregulation of a subset of microRNAs in triple-negative breast cancer is associated with poor survival following neoadjuvant chemotherapy

Abstract

Introduction: Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression. Despite significant research efforts, current therapies are often ineffective against TNBC, resulting in poor survival rates. Therefore, identifying novel molecular markers to predict the response to neoadjuvant chemotherapy (NAC) is essential. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and play crucial roles in various biological processes, including cancer progression. This study aimed to investigate the expression of five miRNAs (miR-26a, miR-125b, miR-181c, miR-181a, and miR-340-5p) in formalin-fixed, paraffin-embedded (FFPE) samples from 20 patients with TNBC and to evaluate their association with clinicopathological features. Methods: miRNAs were isolated from FFPE samples of TNBC patients, and their expression levels were assessed using qRT-PCR. An interactive network-based pathway analysis was performed using IPA software to identify key targets regulated by these miRNAs. Results: Our findings revealed the downregulation of miR-181a, miR-181c, miR-26a, and miR-340-5p in patients who subsequently received NAC using the AC-T regimen. Notably, higher expression levels of these miRNAs were associated with improved overall survival, as demonstrated by Kaplan–Meier survival analysis. Additionally, the pathway analysis identified 17 potential targets regulated by miR-340-5p. Conclusion: Taken together, these findings suggest that the downregulation of specific miRNAs in samples from patients with TNBC may serve as a potential biomarker for predicting the response to NAC.