Disrupted Sleep Speeds up Cancer Growth, Study Finds

Lisa Franchi January 29, 2014

Don’t just sleep. Sleep well. According to a new study, disrupted sleep may spur cancer growth because of its negative effects to the immune system.

In the study, researchers grouped mice into two. One group of mice was allowed to sleep peacefully whilst the other had their sleep disturbed every two minutes with a motorised brush that swept through their cage. This went on for seven days, and then the mice were injected with cells from one of two different kinds of tumours.

All mice developed tumours after 12 days. However, the researchers found that the mice whose sleep was disturbed had tumours twice as bigger as that of those who had quality sleep.

In another similar experiment, which involved implanting tumour cells in the mice’s thigh muscles, researchers found that the mice with disrupted sleep had more aggressive tumours that spread beyond the tissue and into the muscle and bone.

How could this happen?

The researchers theorise that lack of sleep spurs cancer growth due to its negative effect on the immune system. Their findings revealed that well-rested mice had more immune system cells called M1-type tumour-associated macrophages (TAMs) – molecules known to boost the immune system and stop cancer cells. Meanwhile, the sleep-disrupted mice had more immune cells called M2-TAMs, which are known to hinder the immune system and promote tumours through blood vessel growth.

"This study offers biological plausibility to the epidemiological associations between perturbed sleep and cancer outcomes," said Dr David Gozal, M.D., the lead investigator and chairman of paediatrics at the University of Chicago Comer Children’s Hospital. "The take home message is to take care of your sleep quality and quantity like you take care of your bank account."

The research was published in the journal Cancer Research.

Poor sleep is considered a risk factor for many illnesses. Past researches have linked sleep deprivation with a higher risk of stroke, obesity, diabetes, cognitive decline, bone damage, heart disease and premature death.

Source of this article:

Disrupted Sleep Could Spur Cancer Growth Through Immune System Effects, Animal Study Shows