Soy Offers Hope for Enhancing Effectiveness of Mesothelioma Radiation Treatment
Like many foods and drinks that are touted as having healing qualities or extraordinary health benefits, soy has been surrounded by controversy. Some nutritionists and scientists claim that the high-protein, low saturated fat food lowers cholesterol, reduces menopausal symptoms, prevents osteoporosis and prevents prostate and breast cancer. Others claim that too much soy actually increases the risk of cancer. Now, researchers at Wayne State University have found that the natural non-toxic components of soybeans, called soy isoflavones, increase the effectiveness of radiation at killing lung cancer. Radiation is one of the primary treatments for pleural mesothelioma and lung cancer and is used to control the growth or spread of the cancer.
Pleural mesothelioma is a form of lung cancer caused by asbestos exposure and is most commonly found in the outer lining of the lungs called the mesothelium. Mesothelioma is a diffuse malignancy that invades the tissue area causing the boundaries between malignant tissue and healthy tissue to become blurred. Lung cancer, however, is characterized by individual tumor masses with clear boundaries. Even with these differences between the two pulmonary cancers, the treatments are often very similar.
According to the findings published in the April 2011 issue of the Journal of Thoracic Oncology, the soy isoflavones block cancer cells’ DNA repair mechanisms while protecting normal tissue. The research team found that non-small cell lung cancer (NSCLC) cells that were treated with soy isoflavones prior to radiation showed more DNA damage and less repair activity to the cancerous cells than the cells that received only radiation.
Previous research demonstrated that a pure soy mixture enhanced the effects of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors. EGFR is a protein found on the surface of some cells to which epidermal growth factor binds, which causes the cells to divide. However, Wayne State proved that a soy mixture had an even greater antitumor effect during the radiation treatment.
Gilda Hillman, Ph.D., associate professor in the Department of Radiation Oncology at Wayne State University’s School of Medicine and the Karmanos Cancer Institute, and lead researcher said, “These natural soy isoflavones can sensitize cancer cells to the effects of radiotherapy by inhibiting the survival mechanisms that cancer cells activate to protect themselves.” She added, “At the same time, soy isoflavones can also act as antioxidants, which protect normal tissues against unintended damage from the radiotherapy.”
Mesothelioma often has a complex growth pattern with the tumors located close to other organs limiting the ability of oncologists to order radiation treatment in high enough doses to successfully attack the cancer. Although proton beam radiotherapy, a more precise tool for delivering the radiation beams to deep-seated tumors with greater precision is now being used in some treatment centers, this study provides hope to mesothelioma patients that the use of soy will allow preservation of healthy tissue during radiation treatments.
