The most prevalent PTLCs are PTCL not otherwise specified (NOS), angioimmunoblastic T-cell lymphoma (AITL), anaplastic lymphoma kinase–negative (ALK− ALCL), and anaplastic lymphoma kinase-positive anaplastic large cell lymphoma (ALK+ ALCL) [2,3]. The gene discussed is ALK; the disease is anaplastic large cell lymphoma.