Unleashing TNF cytotoxicity to enhance cancer immunotherapy.

Tumor necrosis factor (TNF) is a proinflammatory cytokine that is produced and secreted by cytotoxic lymphocytes upon tumor target recognition. Depending on the context, TNF can mediate either pro-survival or pro-death signals. The potential cytotoxicity of T cell-produced TNF, particularly in the context of T cell-directed immunotherapies, has been largely overlooked. However, a spate of recent studies investigating tumor immune evasion through the application of CRISPR-based gene-editing screens have highlighted TNF-mediated killing as an important component of the mammalian T cell antitumor repertoire. In the context of the current understanding of the role of TNF in antitumor immunity, we discuss these studies and touch on their therapeutic implications. Collectively, we provide an enticing prospect to augment immunotherapy responses through TNF cytotoxicity.