CD8A and breast cancer: Likewise, in experimental mouse models of lung metastatic cancer induced by i.v. injection of breast cancer cells [104] or subcutaneous injection of colorectal cancer cells [103], genetic or pharmacologic loss of eosinophils was associated with diminished CD4+ (Th1) and/or CD8+ T cell recruitment into the TME; and in mice injected with melanoma cells in parallel with Treg ablation, activated eosinophils enhanced tumor rejection when co-transferred with tumor-specific CD8+ T cells [106].