Fig. 1.

Tumor cell dissemination. 1) localized invasion; 2) intravasation; 3) survival in circulation; 4) arrest in the capillary bed; 5) extravasation and migration; 6) stimulation of angiogenesis. In addition to individual CTCs, CTC clusters are also found in patient blood, which have a significantly higher metastatic potential and increased ability to survive. CTCs get help from the platelets as well as immune cells during the escape phase