Stromalsupport of CLL-BC can be reproduced when they are co-cultured with bone marrow stromal celllines.6,17 Indeed, murineMS5 and human HS5 cells significantly reduce the level of CLL-BC spontaneous apoptosis, as assessedby Annexin V labeling and MTP probing (Figures 5a and b and Supplementary Figure 3). Here, ANXA5 is linked to B-cell chronic lymphocytic leukemia.