CD274 and mature T-cell and NK-cell non-Hodgkin lymphoma: Approximately 25% of adult T-cell leukemia/lymphomas (ATLL), a rare PTCL subtype in most of North America, highly express PD-L1 due to the aberrant truncation of the 3′ untranslated region of PD-L1 mRNA, leading to increased stability of the PD-L1 transcript [24].