The viability of CLL cells was analyzed, as in the preceding TEM assays, at 12 hours of culture in suspension alone or onto plate immobilized rhICAM-1 or rhVCAM-1 or other integrin ligands of the extracellular matrix (ECM) including fibronectin (FN), collagen type-1 (CL-1), laminin (LM) or vitronectin (VN). This evidence concerns the gene FN1 and B-cell chronic lymphocytic leukemia.