CD8A and neoplasm: Specifically, the exhausted T-cell cluster C6 exhibits upregulated apoptosis, downregulated MAPK and NF-kappaB signaling, and increased IFN-gamma signaling, whereas C0, the activated tumor-infiltrating CD8 T cells, showed the opposite features, i.e., activated proliferation and differentiation signaling, repression of apoptosis, and increased IL-2 signaling (Fig. 6C).