CTLA4 and diffuse large B-cell lymphoma: Compared with DLBCL–NOS, PMBCL did not show significantly higher PD-L1 expression in B-cells, but showed significantly higher levels of PD-L2 expression in B-cells (P = 0.03; Fig. 4a), lower PD-1 expression in CD8 or CD4-positive T-cells (P = 0.0081 and 0.0082, respectively), and higher CTLA-4 expression (P = 0.01) in T-cells (Fig. 4b).