CCR7 and cancer: There is evidence that different mechanisms other than protease-mediated invasion contribute to cancer cell intravasation: (1) mechanical forces such as interstitial fluid pressure or contractile stress [54,55]; (2) CCR7-mediated chemotaxis of cancer cells toward endothelial cells [56,57]; (3) increased vessel permeability induced by cytokines or growth factors [58,59]; and (4) chemorepellent-induced defects (CCID) in endothelial cells [60].