MMP9 and precursor B-cell acute lymphoblastic leukemia: Additionally, MMP9 in the bone marrow microenvironment (BMM) reduces degradation of the extracellular matrix protein and impairs B-ALL cell invasion; pharmacological inhibition of MMP9 significantly prolonged survival in mice with B-ALL, indicating that MMP9 may act as an adjunctive therapeutic target for B-ALL [48].