CD2 and mature T-cell and NK-cell non-Hodgkin lymphoma: The diagnosis of PTCL-NOS is made based on the presence of heterogeneous morphology, an aberrant T-cell immunophenotype (e.g. commonly expressed CD2, CD3, and CD4, and variablely expressed CD4 or CD8) and a clonal TCR gene rearrangement (2, 11).