ALK and mature T-cell and NK-cell non-Hodgkin lymphoma: PTCL most common subtypes are, in order of incidence, PTCL-not otherwise specified (PTCL-NOS), angioimmunoblastic T-cell lymphoma (AITL), anaplastic large cell lymphoma (ALCL), anaplastic lymphoma kinase–positive (ALCL ALK-positive), anaplastic large cell lymphoma, anaplastic lymphoma kinase–negative (ALCL ALK-negative), and enteropathy-associated T-cell lymphoma (EATL), and each of them is characterized by unique genetic, molecular, histopathologic, and clinical features (2, 4).