ALK and mature T-cell and NK-cell non-Hodgkin lymphoma: The most common subtypes of PTCL are PTCL not otherwise specified (PTCL-NOS), angioimmunoblastic T-cell lymphoma (AITL), anaplastic large-cell lymphoma (ALCL) anaplastic lymphoma kinase present (ALK+), and ALCL/ALK− (72, 78).