MMP9 and cancer: Finally, human plasma was found to be an excellent reservoir for cytokines involved in key cancer hallmarks including: pro-inflammatory cytokines (IL-β1, MIP-1a, TNFα, and RANTES) [68,69], chemokines influencing the invasiveness and migration (SDF-1) [70], cytokines supporting tissue repair/ECM degradation and remodeling (TIMP1, TIMP2, MMP1, and MMP9) [71,72], and cytokines promoting cell growth (INF-γ, PDGF-AB, IL-2, and LIF) [69,73].