CD8A and renal carcinoma: Moreover, systemic treatment with a TK-RR-deficient Western Reserve VACV expressing the FCU1 gene in a mouse orthotopic model of renal carcinoma was associated with infiltration of CD8+ T lymphocytes and a decrease in the proportion of infiltrating Treg lymphocytes into the tumor, thus modifying the ratio of CD8+/CD4+ Treg lymphocytes in favor of CD8+ cytotoxic T cells28.