Resumen
Resistance to chemotherapy is an important problem to be solved in breast cancer research. Tumor-associated macrophages (TAMs) contribute to breast cancer progression, including chemoresistance, and it is important to clarify the altered functions of macrophages following chemotherapy to improve prognosis of breast cancer patients. Here, we conducted in vitro experiments and immunohistochemistry in 116 breast carcinoma tissues to determine whether the secretion of heat shock protein (HSP) 70 from breast cancer cells following chemotherapy affects macrophage function. It was revealed that extracellular HSP70 levels increased following chemotherapy and enhanced the pro-tumorigenic effects of TAMs either directly or indirectly by regulating the expression of transforming growth factor (TGF)-ß in breast cancer cells. Immunohistochemistry demonstrated that HSP70 functions as a poor prognostic factor in conjunction with macrophage infiltration. Targeting HSP70 may therefore be useful in regulating the tumor microenvironment in breast cancer tissues and improving the prognosis of breast cancer patients following chemotherapy.