Despite progress in terms of management, breast cancer still constitutes a major threat to health worldwide. Various microRNAs have been shown to play a fundamental role in tumor biology during development and progression. Therefore, our study was focused on investigating the role of circulating microRNA122 (miR-122) in breast cancer and its clinical utility as a potential easily accessible biomarker for use in the diagnostic and prognostic assessment of breast cancer. Determination of the serum CA15-3 and carcinoembryonic antigen levels was conducted using an enzyme-linked immunosorbent assay. The expression level of miR-122 was determined using real time PCR in 90 breast cancer patients and 60 healthy controls. Higher circulating miR-122 levels were found in breast cancer patients than in controls and higher miR-122 levels were observed in patients who experienced metastasis. Additionally, miR-122, at a cutoff > 2.2, had a sensitivity of 93.33% and a specificity of 90% when used to distinguish breast cancer patients from controls and was able to predict metastasis at a cutoff > 10.9 with a sensitivity of 95.83% and a specificity of 65.15%. Kaplan-Meier survival analysis revealed that high miR-122 expression is significantly associated with decreased overall survival and progression-free survival. This study concludes that circulatory miR-122 could be utilized as a diagnostic and prognostic biomarker in breast cancer patients.
Keywords: Breast cancer; Metastasis; MicroRNA; RT-PCR; miR-122.