A tumor mass consists of many types of cells, including cancer cells, endothelial cells, stem cells, cancer-associated fibroblasts (CAFs), and various immune cells, as well as extracellular matrix (ECM) components (e.g., collagen and hyaluronic acid) and secreted molecules (e.g., TIMP1 and VEGF), collectively termed the tumor microenvironment (TME) [4,5,6]. Here, TIMP1 is linked to cancer.