Objective To detect the expression levels of microRNA-34a(miR-34a) in breast cancer and corresponding normal tissues, and study the correlation between miR-34a and clinicopathology of breast cancer.

Methods The expression levels of miR-34a in 67 breast cancer specimens were detected using qRT-PCR technology, and analyze the correlation between it and clinicopathological factors.

Results The expression level of miR-34a in breast cancer tissue was significantly lower than that in matched adjacent tissue(P < 0.01).The differences of the expression levels of miR-34a in cancer tissues among the patients with different ages, sex, menstrual status, progesterone receptor levels, Ki67 expression and human epidermal growth factor receptor levels were not statistically significant(P>0.05).The differences of the expression levels of miR-34a in cancer tissues tumor among the patients with different tumor diametec lymph node metastasis, pathological type, clinical stage, estrogen receptor(ER) level and triple negative were statistically significant(P < 0.05 to P < 0.01).The expression level of miR-34a in tumor diameter ≤ 2 cm group was higher than that in tumor diameter >2 cm group(P < 0.05), the expression level of miR-34a in lymph node without metastasis group was higher than that in lymph node with metastasis group(P < 0.05), and the expression level of miR-34a in non-invasive group was higher than that in invasive group(P < 0.05).The expression level of miR-34a in stage Ⅰ and Ⅱ groups were higher than that in Ⅲ+Ⅳ group(P < 0.01).The expression level of miR-34a in positive ER group was higher than that in negative ER group(P < 0.01), and the expression level of miR-34a in triple negative group was lower than that in non-triple negative group(P < 0.01).

Conclusions The expression level of miR-34a in breast cancer is low, and the analysis results of various clinical and pathological factors indicates that it may play an important role in the development and prognosis of breast cancer.