IGKV2D-26 and acute lymphoblastic leukemia: In order to further investigate the importance of integrin α5β1 on Ph+ ALL cells, we incubated Ph+ leukemia cells with disintegrin, a peptide inhibitor of integrins, and specific α5 inhibitory antibody, and specially knocked down α5 subunit by shRNA and then tested the Ph+ leukemia engraftment in immunodeficient mice.