Because IFNγ, produced in response to T-cell activation, can modulate distant tumor cells (Hoekstra et al, 2020; Thibaut et al, 2020)—including tumor cells more than 800 μm away (Hoekstra et al, 2020)—IFNγ is likely to play a crucial role in Fas-mediated kill of tumor cells. The gene discussed is IFNG; the disease is neoplasm.