The study, published in the journal Cancer Research, is the first to link fragmented sleep and tumor growth and aggressiveness, Medical Xpress reports.
 

"It's not the tumor, it's the immune system," said lead researcher David Gozal, M.D., chairman of pediatrics at the University of Chicago Comer Children's Hospital. "Fragmented sleep changes how the immune system deals with cancer in ways that make the disease more aggressive."
 

Dr. Gozal added, however, that the study also identified a mechanism that acts like a molecular "toll" to regulate how the immune system responds to sleep deprivation — which might respond to drugs to help boost the immune system.
 

"Fortunately, our study also points to a potential drug target," he said. "Toll-like receptor 4, a biological messenger, helps control activation of the innate immune system. It appears to be a lynchpin for the cancer-promoting effects of sleep loss. The effects of fragmented sleep that we focused on were not seen in mice that lacked this protein."
 

The findings are based on studies of mice, but Dr. Gozal said scientists believe the same mechanisms are at work in humans.
 

"This study offers biological plausibility to the epidemiological associations between perturbed sleep and cancer outcomes," Dr. Gozal said. "The take home message is to take care of your sleep quality and quantity like you take care of your bank account."
 

The Centers for Disease Control and Prevention estimate that about 70 million Americans suffer from chronic sleep problems.
 

"Considering the high prevalence of both sleep disorders and cancer in middle age or older populations," the researchers said, "there are far-reaching implications."