To investigate whether p38 MAPK activation plays a significant functional role in GSK2830371/bortezomib-mediated lethality in MCL cells, Z-138, JVM-2, MAVER-1 and REC-1 cells were exposed to GSK2830371 and bortezomib, either as individual agents or in combination, in the presence or absence of the selective p38 inhibitor SB203580 at 10 μM; annexin V-positive fractions were subsequently analyzed. This evidence concerns the gene ANXA5 and mantle cell lymphoma.