In vivo experiments using a murine model of mammary carcinoma have demonstrated that radiotherapy-induced expression of the chemokine CXCL16 is an important mechanism which mediates the infiltration of CD8+ T effector cells following treatment, as the recruitment of CD8+ T cells and responsiveness to treatment are reduced in mice that are deficient for its ligand (CXCR6) (Matsumura et al., 2008). The gene discussed is CD8A; the disease is breast carcinoma.