MMP9 and osteoarthritis: Second, in cancer and osteoarthritis, GAS5 has been shown to regulate the expression of MMP2 and MMP9, key enzymes that lead to extracellular matrix degradation, a crucial pathological process involved in AAA formation; however, whether GAS5 promotes extracellular matrix degradation through the regulation of MMP2 and MMP9, thereby contributing to AAA formation, also remains unknown.