CD8A and breast cancer: In an experimental metastasis model by intravascular injection of PyMT breast cancer cells, CXCR2 knockout (CXCR2fl/fl::LysMCre/+) mice had less tumor metastasis in the lung than control mice, and CD8+ T cells from the knockout mouse lungs showed efficient tumoricidal activities compared to the T cells from their control mouse lungs [253].