While MMP9’s pro-tumor roles have been documented in other pediatric malignancies—for example, M2-type macrophages in Wilms’ tumor secrete MMP9 to enhance the epithelial–mesenchymal transition (EMT) via a PI3K/AKT-dependent pathway, thereby promoting tumor proliferation and metastasis [43]—it also plays a critical role in sepsis. Here, MMP9 is linked to neoplasm.