CXCR2 and breast cancer: In the inflammatory tumor microenvironment, macrophages, myeloid derived suppressor cells (MDSC), endothelial cells and stromal fibroblasts secrete CXCL1, which activates the NF-kB pathway in CXCR2+BC cells (Wang et al., 2018) and promotes tumor growth, while contributing to local immunosuppression.