Sleep’s Role in Tumor Growth

It has traditionally been understood that much of the body’s healing takes place when we are asleep, and nowhere has this information been more valuable than during the treatment of cancer patients. But a new study coming from Israeli scientists is giving rise to new questions about sleep’s role in tumor growth, and the study results may make a change in how cancer medication is dispensed. According to a report published in the October 3rd journal Nature Communications, scientists from the Weizmann Institute of Science in Israel examined the epidermal growth factor receptor (EGFR), a receptor responsible for the migration and growth of both cancerous and noncancerous cells. It also controls glucocorticoids, which bind to glucocorticoid (GC) receptors in order to reduce inflammation in the body and help to maintain energy levels throughout the day. The scientists discovered that the activity of the EGFT slows down when the GC receptors are attached to its steroid message, a process that takes place during the day. What does all this scientific talk mean? It means that when an EGFR gene has been compromised by mutations (which is effectively what happens when a patient has cancer), tumor cells may end up growing faster when we are asleep. To test their theory, the scientists treated laboratory animals with a cancer drug, dispensing the medication at different times throughout the day. The drug, Lapatinid, is used to treat breast cancer. They found that the mice that received the medication during resting hours had significantly different levels of cell growth from those that were dosed during waking hours, with those treated during waking hours having more growth. This shows that “the rise and fall in the levels of the GC steroids over the course of 24 hours hinder or enable the growth of the cancer,” says the article. The upshot of the research is that, though more experiments need to be done, scientists may start to work to suppress EGFT cell migration during waking hours. “Cancer treatments are often administered in the daytime, just when the patient’s body is suppressing the spread of the cancer on its own,” says Dr. Yose Yarden, a professor at the Weizmann Institute and the study’s co-leader. “What we propose is not a new treatment, but rather a new treatment schedule for some of the current drugs.” The fact that dispensing medication during resting hours rather than during the day is a valuable piece of the puzzle of how sleep helps the body to heal. There have been a significant number of studies that have shown that cancer patients who get extra sleep are far more likely to heal faster and stay in remission for longer periods of time.