Some encouraging clinical responses were observed for patients with good performance status [21] while more recent studies in animal models suggest that direct injection of IL-2 plus an agonist anti-CD40 antibody induces regression of large mesothelioma tumors through a mechanism involving natural killer (NK) cells driven acquisition and/or maintenance of systemic immunity and long-term effector/memory anti-mesothelioma responses [22]. Here, IL2 is linked to mesothelioma.