Other proteins in this pathway such as signal transducer and activator of transcription (STAT1/2) function downstream of JAK signalling and are important mediators of IFN-γ signalling.84 Mutations in STAT proteins that result in loss of function might also cause impaired IFN-γ signalling and resistance to T-cell-mediated killing in cancer cells.81,85. The gene discussed is IFNG; the disease is cancer.