MMP9 and cancer: -Destroys type IV collagen, a major component of the basal membrane, promoting invasion and metastasis [260].-Enhances the bioavailability of VEGF, thereby increasing the amount of VEGF in the tumor microenvironment [261].-MMP9 overexpression is associated with tumor recurrence, metastasis to lymph nodes, and the development of secondary primary cancer [262].