Matrix metalloproteinases （MMPs） are neutral proteases involved in extracellular matrix （ECM） breakdown and remodeling during physiological processes like morphogenesis, angiogenesis, and tissue repair, as well as in pathological conditions such as inflammation, arthritis, and cancer. MMP9, or 92-kDa gelatinase B/type IV collagenase, is secreted by neutrophils, macrophages, and transformed cells. It is critical for tissue remodeling in inflammatory processes and is a key product of macrophages and neutrophils. MMP9 is also released by lymphocytes and stromal cells in response to inflammatory cytokines or integrin-mediated signals. Excessive MMP9 production is linked to tissue damage and degenerative disorders, making its regulation a focus for therapeutic development. Its overexpression in cancer and inflammatory conditions highlights the importance of understanding the mechanisms controlling its expression to identify potential therapeutic targets.