Stressed mice quicker to get skin cancer

Does stress speed up the onset of skin cancer? The answer, in mice anyway, appears to be “yes.” Scientists at the Johns Hopkins Kimmel Cancer Center say that chronic stress may speed up the process in those at high-risk for the disease. Their new study, published in the December issue of the Journal of the American Academy of Dermatology, shows that mice exposed to stressful conditions and cancer-causing UV light develop skin cancers in less than half the time it took for non-stressed mice to grow tumors.

The Hopkins investigators say that if what they are seeing in mice has relevance in man, stress-reducing programs like yoga and meditation may help those at high risk for skin cancer stay healthy longer. “There’s a lot of evidence pointing to the negative effects of chronic stress, which dampens our immune system and impacts various aspects of our health,” says Francisco Tausk, M.D., associate professor of dermatology at Johns Hopkins and director of the study. “But, to help create solid treatment strategies, we need a better understanding of the mechanisms of how stressors affect skin cancer development.”

Tausk exposed 40 mice to the scent of fox urine – the mouse equivalent of big-time stress – and large amounts of UV light. The first skin tumor in one of the mice appeared after eight weeks of testing. Mice exposed only to UV light began developing tumors 13 weeks later. By 21 weeks of testing, 14 of the 40 stressed mice had at least one tumor, and two non-stressed mice had tumors. Most tumors were squamous cell skin cancers, also known as non-melanoma cancers, but which have the potential to spread to other parts of the body.

Chronic stress is known to suppress the activity of immune system cells that recognize foreign invading cells and target them for destruction. Acute stress, which is episodic and time-limited, such as parachuting or riding a roller coaster, may have the opposite effect of chronic stress. “Acute stress actually can rev up the immune system,” Tausk says.

Tausk and his team will conduct more studies to find the cancer pathways influenced by chronic stress. “Stress reduction programs usually are a good option for many people, but we think they may be more important for individuals at high-risk for skin cancer,” he says. Fair-skinned people exposed to large amounts of UV light and patients previously diagnosed with squamous cell skin cancer, genetic diseases or organ transplants that predispose them to the disease are considered high-risk. The investigators urge people concerned about their risk for skin cancer to speak with their health-care provider before starting any stress-reduction or exercise program.

This research was funded by the Johns Hopkins Center for Complementary and Alternative Medicine.

Participants in this research are Jason L. Parker, Sabra L. Klein, Warwick L. Morison, and Xaobu Ye from the Johns Hopkins; Martha McClintock from the University of Chicago; Claudio J. Conti from the M.D. Anderson Cancer Center; and Carlos Nousari from the University of Miami.