Expression of miRNA-206 and miRNA-145 in breast cancer and correlation with prognosis

Abstract

Correlation between microRNA (miRNA)-206 and miRNA-145 expression and prognosis in breast cancer was investigated. Breast cancer specimens and paracancerous tissues of 372 breast cancer patients who underwent surgical resection in the First Affiliated Hospital of Shantou University Medical College from September 2010 to September 2014 were included. qRT-PCR was used to detect the expression of miR-206 and miR-145 in breast cancer and paracancerous tissues, and patients were divided into high and low expression groups according to the median expression level to plot survival curve. Expression levels of miR-145 and miR-206 in breast cancer tissues were 2.24±1.23 and 0.76±0.24, respectively. Expression level of miR-145 was significantly lower, while expression level of miR-206 was significantly higher in tumor tissues than in paracancerous tissues (p<0.05). The 3-year survival rates of miR-145 low expression group and miR-206 high expression group were also lower than that of miR-145 high expression group and miR-206 low expression group, respectively (p<0.05). Expression of miR-206 is upregulated and expression of miR-145 is downregulated in breast cancer, which may have an impact on the prognosis of patients. miR-206 and miR-145 may serve as important indicators to predict prognosis of patients with breast cancer in the future. highest in the United States (3). Turner et al (4) predict that the incidence of breast cancer will exceed 50% within the next 50 years and will become the second most common malignant tumor after gastric cancer. In addition, breast cancer at early stage usually shows no obvious symptoms, and can be easily ignored, leading to the high mortality rate. Hindié and Groheux (5) showed that the 5-year survival rate of breast cancer patients was only 62.4%. Because of its high incidence and mortality, breast cancer has long been a hot clinical research topic. MicroRNAs (miRNAs) have been proven to participate in the development of many types of tumors (6-8). Among them, miRNA-206 and miRNA-145 were proved by Sun et al (9) to be associated with female ovarian cancer. Therefore, we speculate that miRNA-206 and miRNA-145 may also show unique expression in breast cancer. Our study investigated the application values of miRNA-206 and miRNA-145 as prognostic or therapeutic indicators for breast cancer.