The study, published online April 25 in PLoS ONE<\/em>, found that after hairless mice were dosed with ultraviolet rays, the nervous ones \u2014 with a penchant for reticence and risk aversion \u2014 developed more tumors and invasive cancer<\/strong>. Consistent anxiety also came with sensitivity to chronic stress and a dampened immune system<\/strong>. Though other researchers have already linked chronic stress to higher risks for cancer and other maladies, the study is the first to biologically connect the personality trait of high anxiety to greater cancer threats.<\/p>\n \u201cAnxiety may be defined as increased sensitivity to physically existent, or non-existent but perceived or anticipated, stressors<\/strong>,\u201d said stress expert and immunologist Firdaus Dhabhar, PhD, first author of the study.<\/p>\n Dhabhar\u2019s previous work has investigated the balance of \u201cgood\u201d and \u201cbad\u201d stress. Short-lived stressors \u2014 like being chased by a lion, or giving a weighty presentation to your boss \u2014 can actually boost your immune system by preparing your body for battle<\/strong>. But constant stress, such as caring for a disabled loved one, breaks down the body\u2019s ability to fight off disease over time<\/strong>, he said.<\/p>\n The question is: How much stress is too much? Because stress responses vary between individuals, Dhabhar turned to understanding the link between base-level anxiety and actual stress<\/strong>.<\/p>\n For mice, stress comes from striking a balance between exploring to find food and mates, and protecting themselves from danger. Highly anxious mice, Dhabhar hypothesized, would err on the side of avoiding danger. He and his research team placed hairless mice on a raised, cross-shaped track, which had one walkway enclosed by walls and the other open. Then they measured how often each mouse ventured to the open arms. Likewise, he placed them in a large box, half lit and half dark, and noted those that spent the most time in the dark side.<\/p>\n \u201cIt\u2019s similar to the idea that if someone is very anxious they may be more worried about, and less likely to, walk down a dark alley,\u201d said Dhabar, an associate professor of psychiatry and behavioral sciences and a member of the Stanford Cancer Institute and the Stanford Institute for Immunity, Transplantation and Infection.<\/p>\n With their evaluation of anxiety complete, the researchers exposed all the hairless mice to UV rays for 10-minute bouts, three times a week, for 10 weeks \u2014 exposure similar to that of humans who spend too much time in the sun. Tumors cropped up a few months afterward. \u201cThis skin cancer model is really valuable,\u201d Dhabhar said, \u201cbecause it closely mimics human skin cancer.\u201d<\/p>\n Additionally, these types of tumors are vulnerable to an immune system attack. In some cases, the immune system could destroy them, he said.<\/p>\n Though all the mice eventually developed skin cancer, the anxious mice had more tumors and were the only ones to develop invasive forms of cancer.<\/p>\n When he and his team compared the immune responses of the low- and high-anxiety mice, they found that nervous mice had higher levels of immune-suppressing cells called regulatory T cells, which normally thwart overzealous responses. The high-strung mice were also making fewer of the chemical signals that fire up an immune attack on the tumors.<\/p>\n Lastly, the researchers looked at the hormone corticosterone. In mice and other animals, the adrenal system \u2014 the \u201cfight or flight\u201d controller of the body \u2014 secretes corticosterone in response to disease and stress. The levels of this hormone were cranked up in anxious mice, suggesting that they have more sensitive stress sensors and, perhaps, a lower threshold for feeling under the gun.<\/p>\n \u201cIdentifying a psychological trait right at the beginning \u2014 before any experimental manipulation \u2014 and seeing that it can be associated with increased tumors months later, and with biology that can begin to explain mechanisms, was a rewarding surprise,\u201d Dhabhar said.<\/p>\n This hasn’t been tested in humans yet, and that needs to be done, Dhabhar said.<\/p>\n \u201cIt\u2019s bad enough that cancer diagnosis and treatment generates stress and anxiety, but this study shows that anxiety and stress can accelerate cancer progression, thus perpetuating a vicious cycle,\u201d Dhabhar said. \u201cThe goal is to ameliorate or eliminate the effects of anxiety and chronic stress, at least at the time of cancer diagnosis and during treatment<\/strong>.\u201d<\/p>\n The team\u2019s next step will be examining whether knocking down the negative effects of anxiety and stress can increase the benefits of cancer treatment. A shot of anxiety medication, such as Valium, for limited periods of time may be helpful, Dhabhar said. There may also be combinations of drugs and behavioral changes that could be most effective in the long run. \u201cUltimately,\u201d he said, \u201cwe really want to harness the patient\u2019s mind and body while doing everything that medicine can from the outside to maximize treatment success.\u201d<\/p>\n Other Stanford co-authors include Tyson Holmes, PhD, senior research scientist; Eric Neri, database manager and analyst; and Jean Tillie, life science research assistant. The team also collaborated with researchers at the University of Texas and the Ohio State University College of Medicine.<\/p>\n The work was supported by the National Cancer Institute.<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":" From the Stanford University press release by Beth Mole: Worrywarts, fidgety folk and the naturally nervy may have a real cause for concern: accelerated cancer. In a new study led… Read more »<\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[5,10],"tags":[123,27,62],"_links":{"self":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts\/2637"}],"collection":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/comments?post=2637"}],"version-history":[{"count":1,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts\/2637\/revisions"}],"predecessor-version":[{"id":2638,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/posts\/2637\/revisions\/2638"}],"wp:attachment":[{"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/media?parent=2637"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/categories?post=2637"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/therapytoronto.ca\/news\/wp-json\/wp\/v2\/tags?post=2637"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"http:\/\/therapytoronto.ca\/images\/blogpics\/Mice.jpg\" "\\"mice\\"")
Worrywarts, fidgety folk and the naturally nervy may have a real cause for concern: accelerated cancer<\/strong>. In a new study led by researchers at the Stanford University School of Medicine, anxiety-prone mice developed more severe cancer then their calm counterparts<\/strong>.<\/p>\n