AXL and breast cancer: To identify the soluble factors potentially mediating the interaction between macrophages and breast cancer cells, we measured the release of several major cytokines/chemokines by macrophages exposed to the conditioned medium (CM) derived from the AXL-expressing breast cancer cell lines HCC38, MDA-MB-231, and MDA-MB-436, and from the AXL-negative MCF-7 cells.