Conversely, eosinophils have been shown to produce chemokines, such as CCL5, CXCL16, CXCL9, and CXCL10, that actively recruit CD4+ and CD8+ T cells to the primary tumor in a murine model of melanoma (8) and breast cancer pulmonary metastases (31), as well as promote skewing of CD4+ and CD8+ T cells towards an anti-tumorigenic Th1 phenotype in CRC (50). Here, CXCL9 is linked to breast cancer.