ICAM1 and acute lymphoblastic leukemia: To determine whether VCAM-1 blockade would further decrease T-ALL growth and progression in vivo, we transplanted primary LN3 T-ALL cells into Icam1-/- mice and Icam1+/- littermate controls and administered an anti-VCAM-1 blocking antibody or a relevant isotype control antibody after T-ALL establishment (>1% spleen chimerism; Fig. 3g).