In certain lymphomas, such as primary mediastinal large B-cell lymphoma (PMBL), plasmablastic lymphoma, nodular sclerosis, and mixed cellularity cHL, T-cell/histiocyte-rich B-cell lymphoma, as well as virus-associated malignancies (Epstein-Barr virus-associated DLBCL and Human Herpes Virus 8-associated Primary Effusion Lymphoma), PD-L1 expression has also been reported. The gene discussed is CD274; the disease is primary effusion lymphoma.