Blocking Bim expression by gene deletion or epigenetic silencing has a central role in the pathogenesis or the response to anticancer therapeutics in a number of human hematologic malignancies including Burkitt's lymphoma (BL), MCL and various B-cell non-Hodgkin's lymphomas.60, 61, 62 Consistent with these observations, gene-targeting experiments of the bim locus in mice demonstrated a crucial role of Bim in the homeostasis of most immune cells. This evidence concerns the gene BCL2L11 and mantle cell lymphoma.