The main mechanism involves MCs secretion of TNF- α, which is the factor that induces tumor angiogenesis, and MCs activate the PI3K/AKT/GSK3β/AM signaling pathway to promote tumor microangiogenesis [76]; MCs secrete excessive immunosuppressive cytokines such as IL-10 and TGF- β to inhibit the infiltration and function of CD8+ T cells, while CD8+ T cells are the key cell subsets that inhibit tumor growth and progression [59,77]; MCs also promote metastasis and escape of tumor cells from immune responses by upregulating matrix metalloproteinases (such as MMP9) [78]. This evidence concerns the gene MMP9 and neoplasm.