Diagnostic Value of Circulating miR-202 in Early-Stage Breast Cancer in South Korea

Background and objectives: Breast cancer is the most common cancer among women worldwide. Early stage diagnosis is important for predicting increases in treatment success rates and decreases in patient mortality. Recently, circulating biomarkers such as circulating tumor cells, circulating tumor DNA, exosomes, and circulating microRNAs have been examined as blood-based markers for the diagnosis of breast cancer. AlthoughmiR-202has been studied for its function or expression in breast cancer, its potential diagnostic value in a clinical setting remains elusive andmiR-202has not been investigated in South Korea. In this study, we aimed to evaluate the diagnostic utility ofmiR-202in plasma samples of breast cancer patients in South Korea.Materials and Methods:We investigatedmiR-202expression in the plasma of 30 breast cancer patients during diagnosis along with 30 healthy controls in South Korea by quantitative reverse transcription PCR.Results:The results showed that circulatingmiR-202levels were significantly elevated in the breast cancer patients compared with those in healthy controls (p< 0.001). The sensitivity and specificity of circulatingmiR-202were 90.0% and 93.0%, respectively. Additionally, circulatingmiR-202showed high positivity at early stage. The positive rate ofmiR-202was as follows: 100% (10/10) for stage I, 90% (9/10) for stage II, and 80% (8/10) for stage III.miR-202was also a predictor of a 9.6-fold high risk for breast cancer (p< 0.001).Conclusions:Additional alternative molecular biomarkers for diagnosis and management of pre-cancer patients are needed. CirculatingmiR-202might be potential diagnostic tool for detecting early stage breast cancer.