After co-culturing human breast cancer cell lines (MDA-MB-231, MDA-MB-468, and MCF-7) with PMA-induced human monocyte THP-1 cells for 48 h, we found that the siRNA-mediated linc00514 knockdown in breast cancer cells reduced the relative mRNA levels of CD206 and CD163 in THP-1 derived macrophages, both of which were M2 polarization markers of macrophages (Fig. 2a), and that the pcDNA-mediated linc00514 overexpression in breast cancer cells increased the relative mRNA levels of CD206 and CD163 in THP-1 derived macrophages (Fig. 2b). This evidence concerns the gene MRC1 and breast cancer.