MMP9 and neoplasm: gingivalis further secretes gingipains to promote the activation of proMMP9 and form active MMP9, which participates in the destruction of the surrounding matrix of the cell, promotes the inflammation and the invasion and metastasis of OSCC cells.104 Gingipains can exert cytotoxic effects, stimulate host endothelial cells to secrete IL-8, promote tumor angiogenesis and tumor growth, and change T cell functions by degrading T cell surface receptors and enhance OSCC immune escape.105