PLAU and cancer: Tumor invasion and metastasis are hallmarks of cancer progression, involving the complex interplay between cancer cells and their surrounding microenvironment.114 Proteolytic enzymes, such as matrix metalloproteinases (MMPs) and urokinase plasminogen activator (uPA), play critical roles in tumor invasion and metastasis by degrading the extracellular matrix (ECM) and facilitating cancer cell migration.115 Butyrate regulates proteolytic activities by inhibiting uPA and stimulating the activity of tissue inhibitor matrix metalloproteinases (TIMP)-1 and TIMP-2 (Figure 2).