As Fun Goes Up, Cancer Goes Down

Lab research at Ohio State shows that having more fun and a richer social life can fight cancer. When researchers induced cancer in mice but then gave them more living space, more toys and running wheels, they found that their tumors shrank a surprising 77 percent. Five percent of these animals that had cancer went into complete remission, showing no evidence of cancer after three weeks in their wonderful new surroundings.

“Animals’ interaction with the environment has a profound influence on the growth of cancer — more than we knew was possible,” says researcher Matthew During.

During says that the more complex social dimension in the new living arrangements was apparently the key to the decrease in tumor size. The same improvements weren’t seen in animals who only exercised more, so physical activity in and of itself wasn’t the answer.

The animals showed lower levels of a hormone produced by fat called leptin, indicative of a significant shift in metabolism. Their immune systems also appeared to be “ramped up a bit,” During says.

During and his colleague ultimately traced the effect to a growth factor expressed in the hypothalamus called brain-derived neurotrophic factor (BDNF). Further study showed that manipulations designed to increase BDNF levels also reduced tumor burden. In animals lacking BDNF, the benefits of an enriched environment evaporated.

The researchers point out that the findings lend favor to the view that low levels of stress, or certain kinds of stress, can be beneficial. “A lot of people think stress is bad, but our data show the animals aren’t just happy. Antidepressants won’t give you the same effect,” notes During.

In fact, the animals show higher levels of stress hormones known as glucocorticoids. “The goal isn’t to minimize stress, but to live a richer life, socially and physically,” During says. “You want to be challenged.”

The study was published in the July 9, 2010 issue of the journal Cell.