STAT mutations discovered in T cell malignancies. Color-coded representation of the location of each mutant residue within the domain structure of each STAT protein. The majority of mutations in STAT proteins were found within the SH2 domain with mutational hotspots at STAT3 Y640F and D661Y, and for STAT5B at N642H and Y665F. Abbreviations: AITL, angioimmunoblastic T cell lymphoma; ALCL, anaplastic large cell lymphoma; ATLL, adult T cell leukemia/lymphoma; CTCL, cutaneous T cell lymphoma; EATL, enteropathy-associated T cell lymphoma; γδTCL, hepatocellular γδ peripheral T cell lymphoma; NKTCL, extranodal natural killer T cell lymphoma; PTCL-NOS, peripheral T cell lymphoma not otherwise specified; T-ALL, early T cell precursor acute lymphoblastic leukemia; T-LGL, T cell large granular lymphocytic leukemia; T-PLL, T cell prolymphocytic leukemia.