IRF4 and lymphoma: The GCB subtype is CCD10+ or BCL-6+, CD10-, and IRF4/MUM1-, while the non-GCB subtype is CD10- or IRF4/MUM1+ [38]. The Ki-67 index is higher in DLBCL compared to indolent lymphoma due to how it correlates with the degree of aggressiveness of the lymphoma (Figure 4) [6,39].