TNF and neoplasm: More than a decade ago, we and others demonstrated that a very few tumor cell lines undergo apoptosis in response to TNFR2 stimulation due to endogenous TNF production and subsequent TNFR1 activation.38, 39 We, therefore, analyzed the involvement of endogenous TNF and TNFR1 in macrophage necroptosis following TNFR2 activation.