NF-κB activation plays an important role in the adhesion of MCL cells to stromal cells because inhibition of NF-κB activity by treatment of co-cultures with either the Bortezomib (PS341) proteasome inhibitor that targets the NF-κB system or siRNA targeting RELA (Figure S2A), reduces levels of MCL cell adherence to stromal cells compared to non-treated co-cultures (Figure 1D). This evidence concerns the gene RELA and mantle cell lymphoma.