Tumor angiogenesis is a vital process that facilitates tumor growth and survival. It is the process by which a tumor stimulates new blood vessel formation and is a critical step in development that enables tumor expansion, local invasion and dissemination by increasing delivery of oxygen, nutrients, and growth factors. The increased blood vessels also form a route for tumor metastases.
There are naturally occurring proteins that can inhibit angiogenesis. Marsala's gene therapy product E10A uses endostatin, an anti-angiogenic factor, to inhibit angiogenesis and to reduce the supply of blood to the tumor. Deprived of nutrients, tumor growth halts and shrinks.