MMP9 and keloid: The expression of genes that participate in mitochondrial oxidative phosphorylation processes such as MT-CO1, MT-CYB, MT-ND5, MT-CO3, and genes involved in extracellular matrix binding and formation, like COL1A1 and SPARC, were elevated in M2 macrophages in keloids, while the expression of extracellular matrix catabolic proteins as MMP9 was diminished (Supplementary Figure 1B).