MMP9 and discoid lupus erythematosus: Comparison of patients with DLE and SCLE using Ingenuity Pathway Analysis revealed pathways associated with fibrotic processes, and longitudinal microarray analysis of patients with DLE and SCLE revealed sustained elevations of TGF-B1, TGF-BR1, SMAD3, MMP1, MMP9, and SERPINE1 (42).