Mechanism of serum miR-21 in the pathogenesis of familial and triple negative breast cancer.

The aim of this study was to clarify the mechanism of miR-21 in familial and triple-negative breast cancer (TNBC) by exploring the expression of serum miR-21. The sera were collected from healthy women at high risk of breast cancer. miR-39 was employed as the external reference, and real-time fluorescence quantitative PCR was used to detect the expression of serum miR-21 in 77 subjects. The miR-21 expression of the familial breast cancer group, TNBC group, and breast cancer high risk group were significantly higher than those in the normal control group and other breast cancer groups (P less than 0.01). A high serum miR-21 expression level was associated with lymph node metastasis and Ki67 expression (P less than 0.01). Serum miR-21 was closely associated with TNBC and familial breast cancer, and its expression was associated with genetic expression, degree of malignancy, and prognosis.