Comparison of the diagnostic power of serum circulating miR-21, VEGF, and CA15-3 in breast cancer.

Objective: The aim of this study was to assess the clinical utility of serum circulating microRNA-21 (miR-21) in the early diagnosis of breast cancer (BC), and to compare its diagnostic performance with raditional serum biomarkers, vascular endothelial growth factor (VEGF) and carbohydrate antigen 15-3 (CA15-3). Methods: From January 2023 to October 2025, a total of 106 women diagnosed with BC, 69 women with benign breast nodules, and 62 healthy women undergoing routine physical examinations were enrolled at a single institution. Serum levels of miR-21, VEGF, and CA15-3 were measured and compared across groups. Relationships between miR-21 and the traditional markers were analyzed using Spearman correlation analysis. Diagnostic efficacy was assessed via receiver operating characteristic (ROC) curve analysis. Results: Relative expression levels of serum miR-21, VEGF, and CA15-3 were significantly elevated in individuals with BC compared to healthy controls (all Conclusion: Serum circulating miR-21 demonstrated significantly elevated expression in patients with BC and presented superior sensitivity and specificity compared to VEGF and CA15-3. These findings highlight miR-21 as a promising non-invasive biomarker for early breast cancer detection, particularly in distinguishing benign from malignant lesions, potentially reducing unnecessary biopsies. However, limitations include a relatively small sample size and single-center design, necessitating validation in larger, multicenter prospective cohorts. Future studies should explore miR-21's association with molecular subtypes and clinical outcomes to facilitate clinical translation.