CXCL2 and breast cancer: In another model of murine breast cancer, MMTV−Neu (Mouse Mammary Tumor Virus—Neu oncogene) [37], we observed an increase of Cxcl1, Cxcl2, Cxcl3, and Cxcl5 levels in the tumor of MMTV−Neu animals compared to the mammary gland of WT animals (Figure S1).