Objective: To investigate miRNA-639 (miR-639) expression in breast cancer and its relations with growth, invasion and metastasis of the breast cancer. Methods: The miR-639 expression in 60 specimens of breast cancer tissue (30 metastatic cases and 30 non-metastatic cases) and 30 specimens of tumor adjacent tissue, along with human breast cancer MD231 and MCF-7 cells were detected by using fluorescent quantitative PCR. The relationship between miR-639 expression level and clinicopathologic features of breast cancer patients was analyzed. The effects of miR-639 on the proliferation, migration and invasion of breast cancer were evaluated by CCK-8 assay, wound scratch assay and Boyden chamber assays, respectively. Results: MiR-639 expression level in breast cancer tissues was significantly higher than that in adjacent tissue, in metastatic breast cancer tissue was significantly higher than that in non-metastatic tissue, and in highly invasive MD231 cells was significantly higher than that in low invasive MCF-7 cells, with all differences reaching statistical significance (all P<0.05). Among the studied clinicopathologic factors, the miR-639 expression was only associated with the M stage of the breast cancer patients (P<0.01). The proliferative, migratory and invasive abilities of MD231 cells were significantly decreased after miR-639 inhibitor transfection, whereas in MCF-7 cells they were significantly increased after miR-639 transfection (all P<0.05). Conclusion: MiR-639 expression is elevated in breast cancer, and the abilities of proliferation, migration and invasion of breast cancer are increased proportionately with the level of miR-639 expression.

Objective: To investigate the efficacy of neoadjuvant chemotherapy in treatment of triple negative breast cancer (TNBC). Methods: The clinical data of 63 patients with stage I to III TNBC treated from January 2009 to January 2013 were analyzed retrospectively. Of the patients, 31 cases received preoperative neoadjuvant chemotherapy (neoadjuvant chemotherapy group) and 32 cases directly underwent surgery and postoperative adjuvant therapy (postoperative adjuvant therapy group). Sequential taxanes after anthracycline-based regimen was adopted in either neoadjuvant chemotherapy or postoperative adjuvant therapy. The preoperative benefit in neoadjuvant chemotherapy group of patients was analyzed, and the postoperative recurrence, metastasis and survival of the two groups of patients were compared. Results: The overall preoperative benefit rate among the 31 patients in neoadjuvant chemotherapy group was 100%, in which the complete response rate reached 61.29% (19/31). Local recurrence or distant metastasis within postoperative 3 years occurred in 13 cases (41.94%) in neoadjuvant chemotherapy group and 22 cases (68.75%) in postoperative adjuvant therapy group respectively, and the difference between the two groups had statistical significance (χ2=4.585, P<0.05). In neoadjuvant chemotherapy group and postoperative adjuvant therapy group, the 3-year disease-free survival rate was 48.38% and 25.00%, and 5-year overall survival rate was 38.71% and 9.78% respectively, and these two parameters in neoadjuvant chemotherapy group were significantly better than those in postoperative adjuvant therapy group (χ2=4.870, P=0.027; χ2=7.469, P=0.006). Conclusion: Neoadjuvant chemotherapy with an anthracycline-based regimen plus taxanes can effectively benefit the TNBC patients, and its long-term efficacy is also better than that of postoperative adjuvant chemotherapy.

Neoadjuvant chemotherapy is an important part of a systemic treatment of breast cancer, but problems of how to select sensitive drugs, develop individualized treatment plans and estimate the outcome, needs further research. In this paper, the authors address 4 perspectives: the significance of neoadjuvant chemotherapy and the patients suitable to receive it; the use of complete pathologic response as a prognostic marker; selection of drugs and treatment regimens and molecular classification-based neoadjuvant chemotherapy.