ALK and anaplastic large cell lymphoma: PTCLs encompass several subtypes, including PTCL not otherwise specified (PTCL-NOS), ALK-positive ALCL, ALK-negative ALCL, angioimmunoblastic-type T-cell lymphoma (AITL/T follicular helper [TFH] lymphoma), and TFH lymphoma NOS (2022 WHO classification).