MMP-2 and MMP-9 expression in adult and childhood acute lymphatic leukemia(ALL)

In the present study the expression of matrix metalloproteinase-2 (MMP-2) a nd matrix metalloproteinase-9 (MMP-9) in acute lymphatic leukemia (ALL) is studied with immunocytochemical staining in bone marrow aspirate smears fro m 75 patients. The material included 20 adult and 55 pediatric ALL patients . In 65% of the adult ALL cases the immunoreactive protein for either MMP-2 . or MMP-9 or for both the enzymes was seen. A statistically significant co rrelation (P 0.027) with MMP-2 positivity and appearance of extramedullary infiltrates was found in adult ALL, suggesting that the gelatinase activity could be related with increased extravasation of the leukemic cells in ALL . This has to be confirmed in a larger patient population. In pediatric pat ients there were only seven cases (12.7%) out of 55 with positive immunosta ining for either of these metalloproteinases. MMP expression correlated wit h L2 FAB class, high-risk tumor group and T-cell immunophenotype, but not w ith extramedullary presentation in pediatric patients with ALL indicating b asic biological differences between adult and childhood ALL. (C) 2001 Elsev ier Science Ltd. All rights reserved.