The popular novel (and now movie) “the Fault in our Stars” makes use of the phrase “Sleep fights cancer” frequently as the young heroine and her boyfriend each fight for their lives against their own form of the disease. Now researchers out of the University of Chicago have released the results of a laboratory animal study that not only confirms what the book says, but also goes a long way towards explaining why. The scientists subjected half of a group of lab mice afflicted with cancer to sleep deprivation and let the other half sleep naturally and uninterrupted, and found that those who had the interrupted sleep had their tumors grow twice as large. The Chicago researchers determined that by interrupting the animal’s sleep, they were also disrupting their immune system. According to study director David Gozal, chairman of pediatrics at the University of Chicago Comer Children’s Hospital, the immune system generates two different types of macrophages when tumors are present. These are a “hallmark of the immune system’s response to cancer.” One of these tumor-associated macrophages (TAMs) fights tumors while the other does the opposite and suppresses the immune’s system activity. This allows the tumors to grow more rapidly. The study showed that by disrupting the animal’s sleep they were shutting down the body’s immune reaction. The mice that were allowed to sleep had large quantities of the good TAMs that act to protect. Says Gozal, “It’s not the tumor, it’s the immune system. Fragmented sleep changes how the immune system deals with cancer in ways that make the disease more aggressive. The take home message is to take care of your sleep quality and quantity like you take care of your bank account.” For those suffering from any kind of cancer, this is important news, and something that patients are able to do for themselves and perhaps give themselves a sense of control in facing their disease. Not only does sleep play an important role in the immune system’s reaction to the tumors itself, it also helps the body in a number of other ways, including keeping the mind clear in order to remember and learn important treatment information and to counter the impact of chemotherapy, which can often make the mind cloudy. Unfortunately, with cancer’s tumors often comes chronic pain that can disrupt sleep, and many medications used in the treatment of the disease, as well as stress about the disease itself, may also act to cause insomnia. The evidence shows that sleep is an important tool in the body’s attempt to heal itself, so cancer patients struggling with insomnia are urged to talk to their doctor if they are having trouble getting the rest they need. There are also a number of relaxation methods available to cancer patients that may not only help with getting to sleep but may aid in overall stress relief. These include yoga, meditation, massage therapy, aromatherapy, acupuncture and hypnosis.