According to a Wayne State University study in this month's issue of the Journal of Thoracic Oncology, a naturally occurring component in soybeans improves the effectiveness in radiation therapy.
Thoracic oncology is the study of cancers that occur in the chest cavity, so this would include lung cancer, esophageal cancer, and pleural mesothelioma (cancer of the lining of the lung).
The component researchers have been studying are soy isoflavones. According to the recent study, soy isoflavones stop cancer cells' DNA from repairing themselves, and the soy isoflavones can accomplish this while protecting normal tissue in the same area.
In a news release from Wayne State University, Dr. Gilda Hillman says:
"To improve radiotherapy for lung cancer, we are studying the potential of natural non-toxic components of soybeans, called soy isoflavones, to augment the effect of radiation against the tumor cells and at the same time protect normal lung cells against radiation injury."
Dr. Hillman, an associate professor in the Department of Radiation Oncology at Wayne State University's School of Medicine and the Karmanos Cancer Institute, led the team of researchers in the soy-radiation study. Dr Hillman explained:
"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. At the same time, soy isoflavones can also act as antioxidants, which protect normal tissues against unintended damage from the radiotherapy."
Dr. Hillman and the rest of the team found that non-small cell lung cancer cells that were treated with soy isoflavones before radiation showed more DNA damage and less repair activity than cells that received only radiation. Damaging cancer cells' ability to repair themselves is what many chemotherapy drugs aim to do.
The Wayne State researchers used a formulation consisting of the three main isoflavones found in soybeans, including genistein, daidzein and glycitein. (pictured below)
Previous research demonstrated that pure genistein showed antitumor activity in human non-small cell lung cancer (NSCLC) cell lines. Hillman's study showed that the mixture of soy isoflavones had an even greater antitumor effect than pure genistein. The university's news release noted that
the soy mixture also is consistent with the soy isoflavone pills used in clinical studies, which have proven to be safe.
