CD8A and neoplasm: Immunohistochemistry of EL4 tumor sections from vehicle or 90Y-NM600-treated mice at days 3 and 6 after injection showed significantly higher levels (P < 0.0001) of activated tumor-infiltrating (CD8 + ) T-cells at day 6, compared to mice in the vehicle or day 3 post-treatment groups (Fig. 6a, b).