Researchers studying the effects of stress in animal models reported that a socially isolated and stressful environment can speed up the effects of stress.

Dr Suzanne D. Conzen, an associate professor of medicine at the University of Chicago, informed that social isolation can change the expression of genes important in the growth of mammary gland tumors.

These findings were followed by studies on humans and it was found that stress actually affected breast cancer.

Conzen and her colleagues randomly assigned mice to live in isolation or in groups, who were prone to breast cancer genetically. It was found three weeks later that the same mammary glands expression was seen in mice, equivalent to human breast.

The isolated mice also had a higher level of corticosterone stress hormone response than the group-housed mice.

"One of the things we did note is that the isolated animals were much more vigilant, less exploratory. They released more of a stress hormone when we added another stressor to the situation [besides the isolation]", added Cozen.

Thea Tisty who is a pathology professor at the University of California, San Francisco said the research was an exciting beginning.

To summarize the research, it can be said that the actual stress from outside can affect the kind of genes that will get activated or deactivated.