Nature: In sleep, this cancer is spread quietly!

Text ｜ Xu Rui

Circular breast cancer cells under microscope Source: University of Southern California Norris Comprehensive Cancer Center

A study published in "Nature" on June 22 pointed out that breast cancer cells mainly spread to other parts of the body during night sleep, rather than the continuous spread of the whole day that scientists thought. But researchers reminded that this does not mean that cancer patients should not sleep to prevent cancer cells from spreading. Because previous studies have shown that interrupting sleep may worsen breast cancer prognosis.

Nicola Aceto, author of the thesis author and the Federal Institute of Technology in Zurich, Switzerland, pointed out that the above discovery shows that the best time to treat cancer during the day may be more effective.

"At present, most cancers are not treated with tumor cells at a certain time, but that the tumor is there, and you can attack it at any time." ACETO said that people now know more about the progress of cancer in different periods than before. We need to "take the right medicine" better.

ACETO and colleagues have been focusing on a metastatic breast cancer research. In this cancer, cancer cells usually spread to other organs of the body. In this study, they have an unexpected discovery -the cycle tumor cells (CTC, the cells spread out of invasive tumors) in the subject's body are mainly proliferated at night.

After observing the above phenomenon, the researchers decided to further check the 30 breast cancer patients (including 9 unacceptable metastatic cancer patients). They collected blood samples at 10 am and 4 am before the patient underwent cancer surgery. Sample analysis showed that 78%of CTCs were found in night samples, and patients were sleeping at that time.

Researchers conducted similar blood tests for mice who transplanted 4 different types of breast cancer cells. They found that although the types of cancer are different, 87%to 99%of CTCs are from samples collected during animal sleep. In addition, the CTC aggregation in the blood sample of sleep mice is 278 times that of sober mice. The higher the CTC aggregation, the more likely it is to form a new tumor.

ACETO said that although these discoveries are surprising, there is actually a chapter to follow. The immune system will largely be adjusted by the human body's sleep -awakening cycle (day and night rhythm). But people generally believe that cancer tumors do not follow this rhythmic regulation. Obviously, the new discovery has corrected this misunderstanding, but there are still many questions that have not been answered.

"There must be a certain law that spreads cancer cells to the peak of sleep, but we have not found that exact moment, and it is not clear that sleeping more or sleeping will relieve the above problems." ACETO said.

Related thesis information:

https://doi.org/10.1038/s41586-022-04875- y

"China Science News" (2022-06-24 The 2nd edition of the international title "Breast cancer is more likely to spread in sleep")

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Edit | Zhao Lu

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