IL-10 has three main biological activities that may contribute to the paradoxical results in a context-dependent manner: (1) promoting CD8+ T cell (CTL) proliferation and cytolytic activity, (2) inhibiting antigen presentation and production of pro-inflammatory cytokines from antigen-presenting cells (APCs), and (3) alleviating chronic inflammation via tumor-promoting effects. The gene discussed is IL10; the disease is neoplasm.