The level of IL‐34 signal in the lymphoma tissues was often comparable to that of keratinocytes in the skin (Figure 1), which highly express IL‐34.5, 6 It seems that this IL‐34 expression in DLBCL is an ectopic expression since peripheral CD19+ B cells are negative for IL‐34 mRNA even when activated by pokeweed mitogens (Supplementary figure 1). This evidence concerns the gene CD19 and lymphoma.