MMP2 and keloid: Whereas MMP-2 in mature HTS is strongly increased compared to normal tissue, the activity of MMP-9 in such scars is similar to normal skin.53 The highest activity of MMP-2 was found in keloids, followed by hypertrophic scars, normal skin, and atrophic scars.54 Myofibroblasts suppress the expression of the MMP-2 gene; moreover, expression of MMP-2 is inversely related to the level of α-SMA in these cells.55 This means that a potent increase in the activity of MMP-2 in HTS cannot simply be connected with the appearance of myofibroblasts in the wound.