CTSS and cancer: TAMs have been found to secrete a variety of proangiogenic factors, including tumor-necrosis-factor α (TNFα), MMPs, e.g., MMP2, MMP9, and MMP12, serine or cysteine proteinases, such as cathepsins, plasminogen activator (PA), thymidine phosphorylase, as well as growth factors such as angiopoietin 1 and 2 (Ang-1 and Ang-2), VEGF, epidermal growth factor (EGF), transforming growth factor-α and -β (TGF-α and TGF-β), and platelet-derived growth factor (PDGF) which can promote angiogenesis in various cancers [56, 59–61].