Modified Citrus Pectin (MCP in short) is also known as low molecular citrus pectin. It is a water-soluble polysaccharide fiber extracted from cell walls and peels of citrus fruits such as lemon, orange, etc. It is an amazing small molecular dietary fiber. 

How does MCP work with tumor?
The key function towards tumor-----reduce metastasis risk
MCP can compete with Galectin-3 (tumor associated protein, is the “arch-criminal" of tumor growth and metastasis). The following picture clearly shows the function of MCP towards galectin-3. MCP molecule is in linear long-chain structure. After be absorbed into the blood, it can quickly bind to galectin-3, then wrap outside of the cell and block it.