Stress and Cancer
the rate at which some tumors grow in mice can be affected merely by what sort of cages the animals are housed in—the more noisy and stressful, the faster the tumors grow. Other studies show that if you expose rats to electric shocks from which they can eventually escape, they reject transplanted tumors at a normal rate. Take away the capacity to escape, yet give the same total number of shocks, and the rats lose their capacity to reject tumors. Stress mice by putting their cages on a rotating platform (basically, a record player), and there is a tight relationship between the number of rotations and the rate of tumor growth. Substitute Glucocorticoids for the rotation Stressor, and tumor growth is accelerated as well. These are the results of very careful studies performed by some of the best scientists in the field. (Location 2813)
As a first mechanism, the Immune System contains a specialized class of Cells (most notably, natural killer cells) that prevent the spread of tumors. ==Stress suppresses the numbers of circulating natural killer cells== in these studies. A second route is probably non-immunologic. Once a tumor starts growing, it needs enormous amounts of energy, and one of the first things that tumors do is send a signal to the nearest blood vessel to grow a bush of capillaries into the tumor. (Location 2821)
Tumor cells are very good at absorbing Glucose from the bloodstream. Recall the zebra sprinting away from the lion: energy storage has stopped in order to increase concentrations of circulating glucose to be used by the muscles. But, as my own lab reported some years back, when circulating glucose concentrations are elevated in rats during stress, at least one kind of experimental tumor can grab the glucose before the muscle does. Your storehouses of energy, intended for your muscles, are being emptied and inadvertently transferred to the ravenous tumor instead. (Location 2825)
women who have spent long periods (decades in these studies) working night shifts have an increased risk of breast cancer. (Location 2858)
a shifted day/night schedule dramatically decreases the level of a light-responsive hormone called melatonin, and depletion of this hormone greatly increases the risk of a number of types of cancer, including breast cancer. (Location 2859)
So collectively, we have, with the exception of two studies concerning one type of cancer, no overall suggestion that stress increases the risk of cancer in humans. (Location 2882)
When you compare patients who respond to their cancer with a “fighting spirit” (that is, they are optimistic and assertive) with those who collapse into depression, denial, and repression, the former live longer, after controlling for cancer severity. (Location 2891)
the group therapy intervention extended life span an average of eighteen months, a whopping great effect. (Location 2899)
in a 1961 survey, a boggling 90 percent of American physicians said they did not typically reveal a cancer diagnosis to their patients; within two decades, the number was down to 3 percent. (Location 2907)
“I prefer to deal with individuals and effective techniques, and let others take care of the statistics.” (Location 3010)
SIDS kids had thymuses much larger than those of “normal” dead infants. (Location 3060)
Perhaps the best moral is that when doing science (or perhaps when doing anything at all in a society as judgmental as our own), be very careful and very certain before pronouncing something to be the norm—because at that instant, you have made it supremely difficult to ever again look objectively at an exception to that supposed norm. (Location 3077)
see also
Tags: neurobiology science
Superlink: 051 ☣Neurobiology 050 🧠Neuroscience
Source
8 Immunity Stress and Diseases
Created: 16-09-22 16:54