Both TM-MT-MMPs and GPI-MT-MMPs consist of an RXR/KR motif at the propeptide domain end that stands for furin recognition site, which cleaves the propeptide and activates the MT-MMP zymogen.18 MT1-MMP is recognized as one of the most important members of the MMP family and a key player in cancer progression.16,18 Unraveling the exact relationship between the three enzymes, MT1-MMP, MT4-MMP, and MT6-MMP, is essential for more detailed insight into the protein-protein interactions. The gene discussed is MT4; the disease is cancer.