ALK and angioimmunoblastic T-cell lymphoma: According to the 2016 World Health Organization (WHO) classification, nodal T-cell lymphomas include anaplastic lymphoma kinase (ALK)-positive and ALK-negative anaplastic large cell lymphoma (ALCL), angioimmunoblastic T-cell lymphoma (AITL), and PTCL not otherwise specified (PTCL-NOS).