How Your Brain Protects You Against Cancer?

How Your Brain Protects You Against Cancer?

Cancer strikes fear into the hearts of many. Many cancers are being successfully treated these days and cancer is no longer the death sentence it once was, but it’s always better to prevent it. Exercise, diet and a healthy lifestyle are important for doing that. Research shows only around 5 to 10% of cancer cases are due to “bad genetics,” whereas 90 to 95% are related to exposure to things in the environment and lifestyle. Taking a proactive approach to cancer prevention really can have an impact.

Cancer Prevention: Does Your Brain Play a Role?

Your body has its own ways to protect you against the ravages of cancer. Cancer occurs when mutations affect a cell’s genetic material called DNA. A cell’s genetic material is the blueprint it uses to make all the proteins your body needs for health and vitality. When a mutation takes place, it changes how the genetic blueprint “reads.”  It’s like changing a word in an email so that the message reads slightly differently.

Some mutations don’t cause any problems, but others can cause cells to begin to grow too rapidly and out of control. These cells that grow willy nilly and can’t be easily stopped by a cell’s normal control systems is what we refer to as cancer cells.

Fortunately, cells have internal repair systems that help correct mutations or prevent those mutations from being expressed, so cancer doesn’t always develop when you have a “bad” mutation. Now a new study shows another part your body, a portion of your brain may help keep cancer cells from.

Cancer, the Brain and Sleep-Wake Cycles

In your brain is a biological clock that controls a number of factors that are important for health. It orchestrates the release of hormones that regulate how your body functions, its internal rhythms called circadian rhythms, and your sleep-wake cycle. This biological clock is sensitive to light and sets and resets itself based on how much light reaches the light sensors in the back of your eyes called the retina.

When light strikes your eyes during the day and sees total darkness at night, your biological clock and circadian rhythms are set in a manner that’s conducive to health. On the other hand, when you stay up until the wee hours of the night when you should be sleeping or do shift work, it resets your biological clock, throws off your natural rhythms and causes hormones that control appetite and other aspects of health to become out of balance.

 A Protein That Suppresses Cancer Growth

A number of studies show people who work late night shifts and sleep during the day, the opposite of what your body expects, have a higher incidence of certain types of cancer, particularly breast cancer – but why?  Researchers at Virginia Tech University recently found a protein that protects cells against becoming cancerous also helps regulate circadian rhythms. When this protein, called human period 2, functions normally, it interacts with another protein, a tumor suppressor protein, whose job it is to block tumor growth.

What causes this cancer-suppressing protein to not do its job properly? Changes in a person’s sleep-wake cycle. Staying up late at night or working night shifts alters this protein in such a way that it no longer interacts with the suppressor protein that keeps cells from replicating in an uncontrolled manner, what we think of as cancer. It’s another example of how an environmental factor, light exposure at night, affects the risk of developing cancer.

Another Reason to Get Enough Sleep

It’s studies like this that make you want to re-evaluate your sleep habits! A number of studies have found a link between exposure to light at night and an increased risk for breast cancer. One study found women who worked night shifts had a 30% greater risk for developing breast cancer relative to those who worked during the day.

Experts recommend turning off computer devices and other light sources an hour before going to sleep and sleeping in complete darkness. Even small amounts of light disrupt hormones like melatonin and cortisol that help regulate your sleep-wake cycle. Make sure you’re getting 7 to 8 hours of sleep nightly. Skimping on sleep is linked with an increased risk for a variety of health problems, including heart disease, type 2 diabetes, obesity AND a greater risk for premature mortality.

There seems to be a “sweet spot” for optimal sleep, somewhere in the 7 to 8-hour range. Interestingly, long sleep durations, greater than 8 hours, are also linked with greater mortality. A 2014 study published in the American Journal of Epidemiology concluded that sleep duration is a “powerful predictor of mortality.”  Enough said.

The Bottom Line?

Even if you do everything else right – exercise, eat a healthy diet and avoid toxins like cigarette smoke – you still may be at higher risk for health problems, including cancer, if you’re not sleeping enough or exposing your eyes to light at night when your brain expects you to be in darkness. Make sure you’re not “burning the midnight oil” too often and are sleeping in a dark room when you turn in at night.



Eurekalert.org. “Virginia Tech Researchers Connect Sleep Cycle, Cancer Incidence” December 3, 2014.

Pharm Res. Sep 2008; 25(9): 2097-2116.

Science Daily. “Relationship between sleep cycle, cancer found”

JNCI J Natl Cancer Inst (2001) 93 (20): 1557-1562.

doi: 10.1093/jnci/93.20.1557.

National Sleep Foundation. “Lack of Sleep Increases Your Risk of Some Cancers”

Medical Daily. “Lack of Sleep, Light at Night Can Raise Cancer Risk” October 11, 2011.

Am J Epidemiol. 2014 Nov 15;180(10):997-1006. doi: 10.1093/aje/kwu222. Epub 2014 Oct 3.


Related Articles By Cathe:

How Ignoring Your Biological Clock Contributes to Weight Gain

5 Surprising Factors That May Increase Your Risk of Cancer

What Does Science Say about Red Meat and Cancer?

5 Ways Aerobic Exercise Lowers the Risk of Cancer


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