However, testing minimal residual disease (MRD), which is responsible for disease relapse in patients with B-ALL, at the time of death a reduction of GFP+ (BCR-ABL1+) MRD was found in the BM when mice with B-ALL had been treated with ara-C and the MMP-9 inhibitor compared with mice treated with ara-C alone (P = 0.003, Figs. 6e and S10F). Here, MMP9 is linked to acute lymphoblastic leukemia.