Associations of miR-146a and miR-146b expression and breast cancer in very young women

BACKGROUND: MicroRNAs (miRNA) expression profiles might be useful novel biomarkers for tumor diagnostic and histological characterization. OBJECTIVE: Associations of miR-146 expression and breast cancer in very young women needed to be elucidated. METHODS: We investigated expressions of miR-146a, miR-146b and IL-6 in tissues between 120 young women with primary breast cancer and 130 patients with breast fibroadenoma by RT-PCR. The associations between the expression of miR-146, IL-6 and clinical parameters of breast cancer were analyzed. RESULTS: Levels of miR-146a and miR-146b in breast cancer tissues were lower while level of IL-6 was higher compared to the fibroadenoma tissues and pericancerous breast tissues (P < 0.05). Positive associations were found between levels of miR-146a/b and IL-6 in breast cancer tissues and ER-PgR-, HER2/neu-, Ki-67 index >= 20%, tumor size > 2 cm, positive distant metastasis and lymph node metastasis, advanced clinical TNM stages (III-IV) and basal-like phenotype (P < 0.05). CONCLUSION: Down-regulations of miR-146a and miR-146b expression in breast tissues were related to development and deterioration of breast cancer. miR-146a and miR-146b might act as potential biomarkers for young women with breast cancer.