The difference in the proteolytic activity between recombinant MMP-2 and MMP-9 was also observed during the cleavage of Aβ peptides in human neuroblastoma cells and human cerebral microvascular endothelial cells, where MMP-9 was significantly less effective in the degradation of Aβ40 as compared with MMP-2, while Aβ42 was cleaved only by MMP-2 [34]. The gene discussed is MMP9; the disease is neuroblastoma.