Recent progress in T-cell malignancies including adult T-cell leukemia-lymphoma.

T-cell lymphomas represent a heterogeneous group of lymphoid malignancies characterized by marked biological diversity and generally poor clinical outcomes. Recent updates to the fifth edition of the World Health Organization Classification and the 2022 International Consensus Classification have refined the disease entities based on transcription factor profiles, cytokine signatures, and molecular features. Comprehensive genomic and epigenomic analyses have revealed recurrent alterations affecting T-cell receptor signaling, epigenetic regulation, cell-cycle control, and immune pathways, thereby facilitating the development of molecularly targeted therapies. Viral oncogenesis plays a central role in selected subtypes, particularly adult T-cell leukemia-lymphoma and Epstein-Barr virus-associated natural killer/T-cell lymphomas. The accelerated development of molecularly targeted therapies has led to the introduction of several novel agents, while hematopoietic stem cell transplantation also continues to provide an important potentially curative strategy. This issue of Progress in Hematology provides a comprehensive overview of recent advances in molecular pathogenesis, viral biology, therapeutic developments, and transplantation strategies in T-cell lymphomas.