CD8A and carcinoma: Representative data from a healthy beagle and a dog with thyroid carcinoma are shown in Fig. 4A. CXCR4 expression on CD3+CD8- and CD3+CD8+ T cells in dogs with epithelial malignant tumors was significantly higher than that in healthy dogs (P = 0.0005 and P = 0.0402, respectively) (Fig. 4B).