Once cancer cells have invaded surrounding tissues, they must enter the circulatory system (either the bloodstream or lymphatic system) to disseminate throughout the body. This process, known as intravasation, involves the penetration of the basement membrane and the endothelial lining of blood vessels. Cancer cells achieve this through further degradation of ECM components and by exploiting normal cellular processes such as transendothelial migration, typically used by immune cells.
