The pleiotropic cytokine tumor necrosis factor (TNF) is widely accepted as a central player in the multi-faceted tumor microenvironment, showing a dual role as tumor-promoting or tumor-suppressing, depending on the binding to its receptors TNF 1 (TNFR1) and TNF 2 (TNFR2). The gene discussed is TNF; the disease is neoplasm.