CD8A and neoplasm: In the mice treated with anti-CD8 (ie, depleted of CD8+ T cells), tumor progression was rapid, compared with the IgG control groups, and in those depleted of CD8+ T cells and treated with trametinib the antitumor activity of trametinib was attenuated, as evidenced by 4 out of 6 mice developing tumors >300 mm3 after 30 days of trametinib treatment.