T cell lymphoma: time to make discoveries and advance treatment.

T-cell lymphomas are rare and aggressive tumors, and not only basic research but also the establishment of standard therapies and development of novel drugs for these tumors once lagged behind those for B-cell lymphomas. Now, times have changed. Recent progress in genome-wide analysis made it possible to elucidate the molecular pathophysiology of T-cell lymphomas, and will further facilitate the development of individualized treatment. Japan has a terrible form of virally induced T-cell lymphoma known as adult T-cell leukemia/lymphoma (ATL). Japanese researchers have played significant roles in both basic and clinical research, and finally successfully introduced two brand new drugs from Japan, an anti-CCR4 antibody and an EZH1/2 inhibitor. Large phase 3 trials have now established the addition of brentuximab vedotin to conventional chemotherapy as the standard of care for CD30-positive peripheral T-cell lymphoma (PTCL), including ATL. In contrast, most novel drugs for relapsed/refractory PTCL have been approved on the basis of evidence from small phase 2 trials. Patients still have many unmet needs that we must address. This issue of Progress in Hematology focuses on progress in basic and clinical research on PTCL and ATL.