Correlations of the MiR-330 expression with the pathogenesis and prognosis of breast cancer.

OBJECTIVE: To investigate the expression of micro ribonucleic acid-330 (miR-330) in breast cancer tissues and cancer-adjacent tissues as well as the correlations of the miR-330 expression with clinicopathological features and the prognosis of breast cancer patients. PATIENTS AND METHODS: The expression levels of miR-330 in cancer tissues and cancer-adjacent tissues of 120 breast cancer patients with complete follow-up data were detected via the reverse transcription-polymerase chain reaction (RT-PCR). Meanwhile, the expression level of miR-330 in serum of breast cancer patients was measured using enzyme-linked immunosorbent assay (ELISA). The correlations of the expression level of miR-330 with clinicopathological data and the prognosis of breast cancer patients were explored. RESULTS: The expression level of miR-330 in breast cancer tissues was remarkably higher than that in cancer-adjacent tissues, and it was also higher in serum of breast cancer patients than that of healthy controls. In breast cancer patients with axillary lymph node metastasis, the proportion of patients with the high expression of miR-330 [30/54 (55.6%)] was markedly larger than that of patients with the low expression of miR-330 [6/30 (20%)] (p=0.003). In terms of tumor-node-metastasis (TNM) stage, the proportion of patients with the high expression of miR-330 in stage II or above was evidently larger than that of patients with the low expression of miR-330, in which the proportion was 46/60 (77.2%) in stage III and 11/15 (73.3%) in stage IV (p=0.002). Additionally, the tumor size, the histological grade, the expression of human epidermal growth factor receptor 2 (HER2), the expression of hormone receptors and the tissue type, were not related to the expression level of miR-330 (p>0.05). It was manifested in the survival curve that the median survival time was 84.8 months in the miR-330 high expression group and 96.8 months in the miR-330 low expression group, displaying a statistical difference (p=0.01). CONCLUSIONS: MiR-330 is highly expressed in cancer tissues and serum of patients with breast cancer, and it can promote the axillary lymph node metastasis, which is an important factor affecting the prognosis of breast cancer patients. However, no obvious correlations of the expression level of miR-330 with the tumor size, the histological grade, the HER2 expression and the expression of estrogen receptors are found.