B7-H4 expression in human infiltrating ductal carcinoma-associated macrophages

B7-H4 is a co-inhibitory molecule of the B7 family, which is expressed on antigen-presenting cells (APCs) and is able to limit the T-cell immune response. Macrophages act as professional APCs and are important for immunoregulation of the tumor microenvironment in breast cancer. In order to identify the association between the presence of B7-H4 on macrophages and infiltrating ductal carcinoma (IDC), the present study investigated the expression of B7-H4 on macrophages with different polarizations. The expression levels of B7-H4 in IDC tissues were determined using immunohistochemistry, and the expression of B7-H4 on macrophages in the breast IDC microenvironment were determined using western blot analysis and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The expression levels of interleukin (IL)-6 and IL-10 were detected in IDC tissues and the supernatants of polarized macrophages using an enzyme-linked immunosorbent assay and RT-qPCR. The present study demonstrated that B7-H4 was overexpressed in IDC tissues and macrophages. In vitro, M1 and M2 macrophages exhibited different expression levels of B7-H4. IL-6 and -10 exhibited higher expression in the IDC tissues compared with in distal pericarcinomatous tissues. In conclusion, B7-H4 exhibited overexpression in IDC tissues and cultured macrophage cells. Furthermore, M2 macrophages exhibited higher expression levels of B7-H4 compared with the M1 subtype. In addition, IL-6 and -10 may be associated with B7-H4 expression on macrophages of different polarizations in the IDC microenvironment.