TP53 and B-cell chronic lymphocytic leukemia: Moreover, many tumor suppressors and growth regulatory proteins with a known pathogenic role in CLL (e.g. cellular tumor antigen p53, cyclin-dependent kinase inhibitor 1 p21, the effector of Akt signal transduction forkhead box O3 [FOXO3A] and IkappaBα [IkBα], the endogenous inhibitor of NF-kB) are recognized by XPO1 cargo proteins15.