In the context of CLL, the BCR-VLA-4-interaction is likely reciprocal; this means, VLA-4 has not only an effect on the BCR synapse but BCR-engagement conversely induces VLA-4 activation, resulting in conformational changes of the integrin, and thus, stronger tumor cell adhesion to follicular dendritic cells, creating positive feedback to the BCR. Here, BCR is linked to B-cell chronic lymphocytic leukemia.