Prostate cancer cells disseminate from the primary tumor via venous blood vessels (blue), lymph vessels (green), or nerves (orange). Nerve-disseminated cells enter the lymph and all cancer cells in the lymph pass through at least one lymph node before entering the venous blood supply. CTCs are then carried through the body via the blood circulation. CTCs pass through the through the heart and lungs to enter the arterial blood supply. CTCs are carried with the blood through the arterial system, entering distant organ capillary beds at random. Upon reaching a suitable secondary site, such as the bone, cells must extravasate from the blood vessel to colonize the metastatic site. Image printed here with permission from the source: Tim Phelps (C)JHU/AAAM 2016, Department of Art as Applied to Medicine, The Johns Hopkins University School of Medicine.