Expression of miR-146a in triple negative breast cancer and its clinical significance

Triple negative breast cancer (TNBC) has multiple features including high invasiveness, high recurrence and high mortality. MicroRNA (miR) regulates cell proliferation, apoptosis and differentiation, thus participating occurrence and progression of tumors. Study has found abnormal expression of miR-146a in TNBC cells, suggesting its potential involvement. This study aimed to investigate the correlation between miR-146a and TNBC clinical features, in an attempt to investigate if it can work as the marker for predicting disease progression and prognosis. A total of 125 breast cancer patients (including 60 TNBC and 65 non-TNBC cases) were recruited for collecting clinical information and tumor/adjacent tissues. In situ hybridization and qRT-PCR were used to detect expression level of miR-146a. Cox regression was used to screen independent factor predicting prognosis of patients. Positive rate of miR-146a in TNBC tissues was significantly higher in non-TNBC or adjacent tissues, and is significantly correlated with tumor size and histological stage (P<0.05). Those patients with elevated miR-146a expression had lower survival rate than low-expression individuals (P<0.05). Cox regression revealed miR-146a expression as independent factor of TNBC patient prognosis in addition to tumor size and histological stage. TNM stage, lymph node metastasis, age of onset and menstruation are not related with prognosis. MiR-146a is highly expressed in TNBC. Those with high miR-146a had worse prognosis, making miR-146a expression as one independent factor affecting prognosis of patients.