TRBC1 and peripheral T-cell lymphoma, not otherwise specified: Recently, a newly described antibody to the T cell receptor beta chain constant region 1 (TRBC1) has been used to distinguish normal T cells from neoplastic T cells from a range of T cell neoplasms, including peripheral T cell lymphomas (including angioimmunoblastic T cell lymphoma, adult T cell lymphoma/leukemia, and peripheral T cell lymphoma, NOS), T cell large granular lymphocytic leukemia, T cell prolymphocytic leukemia, and Sezary syndrome, by flow cytometric analysis of peripheral blood, bone marrow, and lymphoid tissues [30].