Plasma miR-141-3p as a Potential Diagnostic Biomarker for Early Breast Cancer and a Functional Regulator with Tumor-Suppressive Effects in Luminal A Breast Cancer Cells.

Objective

Breast cancer (BC) remains the most common malignancy in women worldwide, highlighting the need for reliable non-invasive biomarkers for early detection. miR-141-3p, a member of the miR-200 family, has shown context-dependent roles in tumorigenesis, but its diagnostic specificity and clinical relevance in the plasma of patients with BC remain incompletely understood. Therefore, this study aimed to assess the diagnostic potential and functional role of miR-141-3p in BC.

Methods

Plasma miR-141-3p levels were quantified in breast cancer patients and healthy controls using RT-qPCR. Diagnostic capacity was evaluated via receiver‑operating characteristic (ROC) analysis. Associations between circulating miR-141-3p expression and BC risk were assessed using odds ratios (ORs). In vitro functional assays in MCF‑7 cells (miR‑141‑3p overexpression) examined effects on proliferation, migration, and regulation of target genes.

Results

Circulating miR-141-3p was significantly upregulated in BC patients. ROC analysis yielded an AUC of 0.877 (95% CI: 0.782-0.971), demonstrating good diagnostic performance. No statistically significant stage-dependent difference was observed, suggesting that circulating miR-141-3p dysregulation may not simply reflect tumour burden. In vitro, miR‑141‑3p overexpression suppressed MCF‑7 cell proliferation and migration and reduced expression of EMT‑associated markers. Furthermore, strong inverse correlations were observed between miR‑141‑3p levels and its predicted oncogenic targets.

Conclusion

Circulating miR‑141‑3p shows promise as a non‑invasive biomarker for BC detection and risk discrimination, although its specificity as a stand-alone marker may be limited. Its in vitro effects on proliferation, migration, and EMT markers indicate potential functional relevance. Further validation in larger cohorts and through in vivo studies is warranted.