Under controlled experimental conditions, bone marrow–derived macrophages (BMDMs) and bone marrow–derived dendritic cells (BMDCs) cultured in conditioned media (CM) of ER stressed cancer cells develop a de novo UPR and acquire a mixed IIS phenotype [26,28] characterized by the transcriptional up-regulation of the tumorigenic proinflammatory cytokines IL-6, tumor necrosis factor α (TNFα), and IL-23 [32–34], and contextually of the immune-suppressive enzyme Arginase1 (Arg1) [35]. The gene discussed is TNF; the disease is cancer.