Genetic knock-down of the catalytic E1 subunit, SAE2, in the MCL cell lines Jeko, Z-138 and UPN-1 by shRNA led to a significant loss in the total number of viable cells, thus supporting the importance of sumoylation in promoting MCL cell survival (Fig. 1E) Similarly, downregulation of SAE1 in Jeko cells also had a similar reduction of total viable cells (Additional file 1: Fig. S4). This evidence concerns the gene SAE1 and mantle cell lymphoma.