Main findings of the study and their potential consequences are summarized. Recurrent gains (indicated by an additional gene copy on one allele) of 16p11.2-13.3 include the ABCC1 gene. This may lead to increased ABCC1 expression, and the increased expression of this multidrug transporter may cause chemoresistance of the lymphoma cells. Increased gene copy numbers for components of the NF-κB pathway, including MAP3K14 (NIK) and IKBKB, may cause increased expression of these positive regulators of NF-κB activation and consequently contribute to the strong constitutive NF-κB activity in HRS cells. The NF-κB pathway is displayed in a simplified way, not discriminating the canonical and noncanonical pathway. The CD40 gains may contribute to strong CD40 expression in a setting where most B cell–typical genes are down-regulated. CD40 promotes the interaction of HRS cells with surrounding CD40 ligand-expressing T cells and likely also contributes to NF-κB activity in HRS cells.