Cytotoxic T-cells are further defined by CD8 expression in conjunction with CD3, along with cytoplasmic cytotoxic granules, including perforin, T-cell restricted intracellular antigen (TIA-1), and granzyme B. In the PTCL-NOS subtype, cytotoxic phenotypes are generally associated with more aggressive clinical behavior, although this is not universal [8,9,10,11]. This evidence concerns the gene NOS2 and mature T-cell and NK-cell non-Hodgkin lymphoma.