IFN-γ is a cytokine produced and secreted by effector T cells and APC that act in the activation of IFN receptor signalling molecule Janus kinase 2 (JAK2) and signal transducers and activators of transcription-1 (STAT1), contributing to immune cell activation and regulation of T cell responses, and can also directly induce tumor cell death. The gene discussed is JAK2; the disease is neoplasm.