Mature T-cell and NK-cell leukemias represent a clinically heterogeneous group of diseases, ranging from indolent expansions of large granular lymphocytes, to aggressive diseases that are associated with a fulminant clinical course. Recent advances in genomic methodologies have massively increased the understanding of the pathogenesis of this group of diseases. While the entities are genetically heterogeneous, JAK-STAT pathway activation appears to be important across these disorders. The identification of constitutively activated pathways and the emergence of novel targeted pharmaceutical agents raise the expectation that more effective therapies will be identified for these disorders in the coming years.
