Medical staff at the University of Chicago’s Comer Children’s Hospital looked at the epidemiologic relationship between disturbed sleep and developing cancer, and the findings were published in the Journal of Cancer Research. During the mice’s normal sleep period, researchers ran a quiet motorized brush through their cages every two minutes, forcing them to wake up and then letting them sleep again. Another group of mice served as a control control group, and sleep was not disturbed. After seven days in this environment, both groups of mice were injected with tumor cells. Within 9-12 days, all of the mice produced visible tumors. The researchers evaluated them four weeks after inoculation. The results of the study showed that the tumors were twice as large in the mice with disturbed sleep compared to the mice with normal sleep. Subsequent laboratory tests found that when tumor cells were implanted in the thigh muscles of the mice, the tumors were more aggressive in the sleep-disrupted group. The researchers found that frequent awakenings during sleep increased the risk of cancer growth and aggressive tumor growth, and even suppressed the immune system’s ability to detect precancerous lesions early. Researchers believe that fragmented sleep changes the way the immune system processes cancer, making the disease more aggressive. The study concludes that to avoid cancer, people should improve the quality of their sleep.