PRDM1 and aneurysmal bone cyst: Interestingly, both genes, PIM1 (40% in ABC vs 15% in GCB) and PRDM1 (25% vs less than 5%), show high prevalence of activating mutations in ABC-DLBCL [14] as indicated by over-expression of spot modules E and H in the SOM portrait of ABC-DLBCL but not in GCB-DLBCL (see Fig. 4).