Together with our demonstrations of local heterochromatinization of telomeric regions [32,33] and in agreement with the recently discovered role for the multifunctional transcriptional positive coactivator 4 (PC4) in targeting heterochromatinization in non-neuronal human cells [38], different levels of RelB expression between female and male CLL cells may involve a cell differentiation- and/or gender-specific factor that controls a dynamic state of chromatin region containing RELB. Here, RELB is linked to B-cell chronic lymphocytic leukemia.