JAK2 and breast cancer: In a cohort of 461 breast cancer patients, we evaluated the prognostic significance of IFN-γ as a single gene as well as an IFN-γ gene expression signature composed of IFN-γ and genes downstream in the IFN-γ pathway: IFN-γ receptor 1, IFN-γ receptor 2, the tyrosine kinases JAK1 and JAK2, as well as the transcription factors STAT1 and IRF1 [7] (Table 1).