Due to their ability to degrade type IV collagen and gelatin, which are the main constituents of basal lamina, MMP-2 (gelatinase A, 72 kDa type IV collagenase) and MMP-9 (gelatinase B, 92 kDa type IV collagenase) are the most extensively studied subfamily of MMPs in the course of MS. The gene discussed is MMP9; the disease is myeloid sarcoma.