Dysregulation of the TCR pathway is a common feature of ATL, PTCL, and AITL, whereas the JAK/STAT pathway is frequently altered in PTCL with a cytotoxic immunophenotype ALK-positive or negative anaplastic large cell lymphoma (ALCL), breast-implant-associated-ALCL (Bi-ALCL), cytotoxic PTCL-NOS, and extra-nodal NK/T-cell lymphoma, nasal-type (ENKTCL). The gene discussed is ALK; the disease is anaplastic large cell lymphoma.