Flow cytometric analysis of peripheral blood showed the majority of lymphocytes were CD3+ cells (95.4%) and a CD4/CD8 ratio of 27.4:1 (range, 0.5–2:1), with the majority of CD4+ cells (92.9%) showing a CD7–CD26– phenotype, indicating the peripheral blood involvement of lymphoma (Figure 1C). This evidence concerns the gene DPP4 and lymphoma.