CD5 and B-cell chronic lymphocytic leukemia: After excluding patients with CLL/SLL and MCL (because their cases arise from CD5-positive B-cells by definition), among 62 cases positive for T-cell marker(s), the most frequently expressed T-cell marker was CD5 (n = 43), followed by CD8 (n = 18), CD7 (n = 10), CD2 (n = 2), and CD4 (n = 1) (Figure 1).