Scientists find out how cancer hijacks immune system for cell growth

• Now scientists led by MIT Professor Robert Weinberg, a member of the Whitehead Institute, have discovered the process by which tumors hijack normal wound-healing processes for their own purposes.
• The research, reported in the May 6 issue of the journal Cell, began when Akira Orimo, a postdoctoral scientist in Weinberg's lab, investigated the nature of stromal cells in breast cancer tumors.
• Stromal cells form the connective tissue in a mammal's organs and glands.
• They also form the connective tissue inside tumors, which are composed mostly of cancer cells and stromal cells.
• Researchers wondered if the stromal cells simply hold the tumor together or if they work with cancer cells to promote the tumor's growth.
• Orimo found that a particular protein produced by the stromal cells, called SDF-1, is a key player in helping tumors grow.
• SDF-1 interacts with a class of cells called endothelial precursor cells.
• Found primarily in the blood, endothelial cells travel throughout the body and aid wounded tissue by enabling new blood vessels to form, a process called angiogenesis.
• The stromal cells in the breast cancer tumor produce SDF-1, which in turn persuades these endothelial precursor cells to enter the tumor.
• Once they do, they help the tumor to form its own robust network of blood vessels, weaving a circulatory system throughout the tumor mass.
• Additional co-authors of the Cell paper are from the Brigham and Women's Hospital, Harvard Medical School, Massachusetts General Hospital, Baylor College of Medicine and the Institute Pasteur.
• This work was funded by Merck/MIT, the National Institutes of Health, the Ludwig Trust, the Breast Cancer Research Foundation, Uehara Memorial Foundation, Sankyo Foundation of Life Science, and a U.S. Army Pre-doctoral Breast Cancer Fellowship.