MMP9 and B-cell chronic lymphocytic leukemia: We report for the first time the following findings: 1) upon an apoptotic stimulus, MMP-9 is transcriptionally upregulated and localizes to the surface of early apoptotic cells; 2) MMP-9 by itself or present in stroma induces CLL cell drug resistance; 3) MEC-1 cells stably transfected with MMP-9 show increased survival upon drug treatment; 4) the MMP-9 anti-apoptotic effect involves modulation of anti- and pro-apoptotic proteins from the Bcl-2 family.