Alternatively, upregulated MMP-2 and MMP-9 expression might be caused by abnormal metabolic stimuli resulting from the presence of diabetes, which is known to induce the dysfunction of several intracellular signal transduction cascades; for example, protein kinase activity and the accumulation of advanced glycation end products might induce the generation of MMP overproduction under diabetic conditions (64–68). The gene discussed is MMP9; the disease is diabetes mellitus.