Study on the relationship between miR-520g and the development of breast cancer.

OBJECTIVE Breast cancer (BC) is one of the most common malignant tumors occurred in women. There is no sensitive and specific marker for early diagnosis, treatment and prognosis of breast cancer. It is suggested that miRNA may be a potential tumor marker for breast cancer. Mir-520g is considered to be associated with many tumors. This study aims to test the expression of mir-520g in peripheral blood of BC patients and healthy control. We also explored the relationship between mir-520g and several prognostic factors in breast cancer patients. PATIENTS AND METHODS The peripheral blood of 86 cases with breast cancer (including 18 cases with stage 0, 24 cases of phase I, 20 cases of stage II, 24 cases of stage III) and 26 cases of healthy subjects were collected. The miR-520g level was measured by real-time quantitative PCR (RT qPCR) method. The correlation between plasma miR-520g level and the clinical stage, molecular subtype, receptors' expression and other factors related to the prognosis of the patients were examined. RESULTS Plasma mir-520g expression levels were significantly higher in BC patients with lymph node metastatic and low differentiation degree grade (p = 0.033 and 0.016), and plasma miR-520g expression was significantly higher in breast cancer patients with mammary gland invasion (p < 0.01) and low expressed p53 (p = 0.0039). CONCLUSIONS Highly expressed mir-520g is associated with lymph node metastasis and low differentiation of breast cancer, and also is associated with mammary gland invasion in breast cancer. This study suggests that mir-520g may be associated with some important prognostic factors in breast cancer patients, and may have a potential value for breast cancer marker.