VCAM1 and acute lymphoblastic leukemia: In this regard, VLA‐4/VCAM‐1 interactions have been involved in the induction of chemoresistance in B‐cell ALL [20, 44] as well as other haematological malignancies [45, 46], and our data show that, as in bone marrow, the blockade of VLA‐4 signalling in BCP‐ALL cells is also able to partially revert the chemoresistance induced by CP fibroblasts.