ENG and cancer: [6] MMP-14, also known as MT1-MMP is one of six membrane-type MMPs, and has been widely studied for its role in cancer progression and metastasis. [7], [8], [9], [10] Through over-expression systems in COS-7 cells, Hawinkels et al showed MMP-14 was the cleavage protease of membrane bound endoglin, producing soluble endoglin that is then released. [11] Through mutagenesis experiments, they mapped the cleavage point on membrane bound endoglin to a specific glycine-leucine point near the transmembrane domain region.