Does it matter to cancer whether it's day or night? The answer seems to be 'yes'.
Scientists have known that the cells in plants and animals go through periods of high and low activity. These patterns are called circadian rhythms. The impact of circadian rhythms on the spread of cancer was recently investigated in breast cancer patients and in mice. Samples of blood were taken when the patients (or mice) were awake and active and then when they were resting at night. The samples were then examined to see how many cancer cells they contained. The results were very clear!
Many more cancer cells were found in the samples taken at night, The tumors in the patients and mice were shedding more cells into circulation when the patients/mice were resting. Exactly why this is happening is under investigation, but is linked to changes in hormoneA chemical produced by cells that alters the activity of other cells. The chemicals may be lipids, such as testosterone and estrogen or proteins like insulin. Hormones may act at locations far from their site of origin. Estrogen, for example, is produced primarily by cells in the ovaries but acts on cells in the breast and elsewhere. and sugar levels. The results could be very important, because blocking the spread of cancer is critical. Knowing when to give treatments, and what precisely to give, is essential.
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