As predicted from prior reports, most T-CUS detected by TRBC1 staining has an immunophenotype reminiscent of CD8-positive T-cell large granular lymphocytes, with a clone size that only occasionally overlaps with that seen in T-cell large granular lymphocytic leukemia (T-LGLL) [44]. The gene discussed is TRBC1; the disease is T-cell large granular lymphocyte leukemia.