Consistently, urokinase-type plasminogen activator receptor (uPAR), the receptor for urokinase plasminogen activator (uPA), known to be involved in degradation of the ECM, as well as invasion and metastasis of malignant tumors27, was higher in the plasma of WT mice with B-ALL than healthy mice (Supplementary Fig. 13E). This evidence concerns the gene PLAU and precursor B-cell acute lymphoblastic leukemia.