Cancer is a complicated disease that has posed numerous problems for the medical community. Questions regarding how it forms to how to prevent and treat the disease have challenged medical research for decades. While a great deal of time and effort has been expended to develop drugs and therapeutic approaches, new research has revealed that in animal models, living conditions may play a role.

A new study, published in the journal Cell, has found that when animals get an upgrade in their social life and their environment, their tumors shrank and in some cases, their cancers went into spontaneous remission. The new data suggests that factors that can influence the emotional state of an individual, including where they live and their social connections, may play a role in the development cancer.

Researchers have observed that when a living environment is rich in physical and emotional stimulation, it can result in a small degree of mild stress. This stress can actually be beneficial and as a consequence, temper cancer progression. This, in turn, could have implications in the treatment of cancer in people.

The reason for this is because a rich living environment activates a special pathway in the brain that communicates with fat tissue. The pathway, known as the hypothalamic-sympathoneural-adipocyte (HAS), tells fat to stop releasing the hormone leptin. Leptin functions to curtail appetite, but has also been implicated in promoting cancer growth.

The findings seem to conflict with the conventional wisdom that people suffering from cancer should avoid all forms of stress. In fact, an increase in life challenges that can lead to the release of some stress hormones might actually be of benefit due to the activation of the HSA pathway, which is also present in human beings.

In the study in question, researchers housed the test animals in large living spaces that included toys, exercise equipment, and a variety of locations suitable for hiding in. Control animals were given a standard housing arrangement with no toys and limited social interaction.

After three weeks of observation, the animals in the richer housing environment developed tumors that were half the size of the control mice. After six weeks, those same tumors were 80 percent smaller in size, with nearly 20 percent of the enriched group showing no visible tumors at all.

Researchers took the experiment a step further and looked for any changes in metabolism, particularly the hormones in the blood. For the test group, leptin showed the most significant decline. Further inquiry demonstrated that leptin and the HSA pathway did affect tumor growth, and by blocking the hormone, tumor growth was tempered.

Furthermore, in the test (enriched) group, gene expression that influences food consumption and the balance of energy was much higher than the control group. Blocking this gene resulted in enlarged tumors in even the animals living in the enriched environment.

Though more work needs to be done before any conclusions can be drawn, the findings are nonetheless interesting and suggest that a rich and social living environment might be important for maintaining good health, a fact that many people might already be familiar with.