The most common subtypes include peripheral T-cell lymphoma, non-otherwise specified (PTCL-NOS), extra-nodal natural killer (NK)/T cell lymphoma, nasal type (ENKTL), angioimmunoblastic T cell lymphoma (AITL), anaplastic lymphoma kinase positive anaplastic large cell lymphoma (ALK+ ALCL) and anaplastic lymphoma kinase negative anaplastic large cell lymphoma (ALK− ALCL). Here, ALK is linked to mature T-cell and NK-cell non-Hodgkin lymphoma.