Expression of matrix metalloproteinase (MMP) and tissue inhibitor of MMP (TIMP) genes in blasts of infant acute lymphoblastic leukemia with organ involvement.

The mRNA contents of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of MMP (TIMP)-1 and TIMP-2 in leukemia cells from 33 infants with acute lymphoblastic leukemia (ALL) were quantified at initial presentation, and the correlation between their expression and patient clinical characteristics was examined. The mRNA contents of MMP-2 and MMP-9 were not associated with any patient characteristics. Positive correlation was found between hepatosplenomegaly and the MMP-2/TIMP-1 and MMP-2/TIMP-2 ratios (p=0.005 and 0.009) and between CNS involvement and the MMP-2/TIMP-2 ratio (p=0.012). The results suggest that MMP/TIMP balance is closely related to the infiltration of leukemia cells into extramedullary organs.