Cells in malignant tumors are abnormal and divide without control or order. These cancer cells can invade and destroy the tissue around them. Cancer cells can also break away from a malignant tumor. Angiogenesis Researchers say one of the most important things required for metastasis to occur is the growth of a new network of blood vessels. This process of forming new blood vessels is called angiogenesis.
Angiogenesis is a normal biological process.
For example, angiogenesis is necessary for the repair or regeneration of tissue during wound healing. Tumor angiogenesis, however, is different. NCI says tumor angiogenesis is the growth of a network of blood vessels that penetrates into cancerous growths and supplies them with nutrients and oxygen and removes waste products. NCI says tumor angiogenesis starts with cancerous tumor cells releasing molecules that send signals to activate genes in the host tissue that, in turn, make proteins to encourage growth of new blood vessels. Certain molecules can either activate or inhibit angiogenesis.