In xenograft models of aggressive B-cell lymphoma and MM ABT-263 promoted significant efficacy of clinically relevant chemotherapeutic regimens.140 A detailed activity screen revealed that ABT-263 enhances the response of multiple chemotherapeutic regimens, for example, rituximab, rapamycine, rituximab–cyclophosphamide-adriamycin-vincristine-prednisone, and bortezomib, in several models of hematologic malignancies.141 However, owing to the crucial role of Bcl-xl in platelet homeostasis34 the therapeutic use of ABT-263 was associated with transient thrombocytopenia in preclinical trials.142. This evidence concerns the gene BCL2L1 and Thrombocytopenia.