December 14, 2011 – Malignant pleural mesothelioma typically begins in the lining of the chest cavity and then spreads to other organs and parts of the body. For many years, researchers have believed that blood platelets, the cells that normally promote blood clotting and wound healing, promotes the spread, or metastasis, of cancer. New research published by researchers at Massachusetts Institute of Technology presents an even clearer picture of platelets’ role in how cancer cells break away from the original tumors and spread to other organs and tissue. These findings may be instrumental in developing treatments for the prevention of the advancement of cancer, including mesothelioma, if caught before it spreads, or metastasizes.
For many years, researchers have assumed that blood platelets played an active role in the advancement of cancer in several ways. First, they contain growth factors that stimulate growth in all human cells including cancer cells. Second, platelets help the malignant cells to clump, enabling them to get stuck in new locations more easily. Some researchers, however, have suspected that platelets play a more prominent role in the spread of cancer. They have surmised that platelets actually effect epithelial-mesenchymal transition, the process a cancer cell goes through before it metastasizes when it becomes less adhesive and more mobile.
In this latest study, the MIT researchers found that when they depleted the growth factors from the platelets interacting with cancer cells before epithelial-mesenchymal transition, metastasis did not occur. Further research showed cancer cells would not become metastatic if exposed ONLY to the growth factor, suggesting that the cancer cells depend on additional chemical signals from the platelets before they are prepared to spread. This research demonstrates that blood platelets not only help cancer cells grow, clump and adhere to new locations, they actually provide the chemical stimuli for metastasis.