Plasma miR-221 as a Predictive Biomarker for Chemoresistance in Breast Cancer Patients who Previously Received Neoadjuvant Chemotherapy

Background: Neoadjuvant chemotherapy (NAC) is increasingly being used in breast cancer treatment. Research has revealed an elevated expression of miR-221 in adriamycin-resistant MCF-7/ADR cells. This study aimed to explore the potential role of miR-221 as a biomarker for chemosensitivity in breast cancer patients who previously received NAC. Patients and Methods: The expression levels of circulating miR-221 in the plasma of 93 breast cancer patients who previously received NAC and in 32 healthy individuals were assessed. The correlations between miR-221 and clinicopathological features and chemosensitivity were also analysed. Results: The expression level of miR-221 was significantly associated with hormone receptor (HR) status (p = 0.008). Patients with higher plasma miR-221 levels tended to be HR-negative. Patients with different miR-221 levels had significant differences in the overall response rate (p = 0.044) but not in the pathologic complete response rate (p = 0.477). Conclusion: Our results indicate that plasma miR-221 may be a predictive biomarker for sensitivity to NAC in breast cancer patients.