The Janus kinase (JAK)–signal transducer of activators of transcription (STAT) pathway is
now recognized as an evolutionarily conserved signaling pathway employed by diverse
cytokines, interferons, growth factors, and related molecules. This pathway provides an
elegant and remarkably straightforward mechanism whereby extracellular factors control
gene expression. It thus serves as a fundamental paradigm for how cells sense
environmental cues and interpret these signals to regulate cell growth and differentiation …