CTLA4 and neoplasm: Indeed, we found that tumor growth was significantly reduced in mice treated with combined IL-6– and CTLA‐4–blocking Abs compared with mice treated with isotype control Abs (P = 0.0001), single-agent CTLA-4 blockade (P = 0.0207), or IL-6 blockade (P = 0.0002) (Figure 1B).