While the scientific community believed that breast tumors continuously release metastatic cells, the Swiss scientific team discovered that cancer cells that circulate and later form metastases occur primarily during sleep. ..
This is the main discovery of a study of 30 patients and mouse models published in the Journal Nature, led by researchers at the Ecole Polytechnic Federal (ETH) Zurich, University of Basel Hospital, and University of Basel.
According to the World Health Organization (WHO), breast cancer is one of the most common forms of cancer. Every year, about 2.3 million people worldwide suffer from the disease.
If the doctor detects the cancer in time, the patient usually responds well to the treatment. But if the cancer has already spread, things will be much more difficult, ETH recalls.
Metastasis occurs when circulating cancer cells move away from the original tumor, travel through blood vessels, and form new tumors in other organs.
So far, cancer research has paid less attention to this issue of when tumors release metastatic cells, according to the director of the study.
This new study has drawn “amazing conclusions”: the circulating cancer cells that metastasize later occur primarily during the sleep phase.
A hormone regulated by circadian rhythm-controlled metastasis.
“Tumors awaken when the affected person is asleep,” summarizes research leader Nicola Aceto, a professor of molecular oncology at ETH Zurich.
During a study of 30 cancer patients and mice, researchers discovered that the tumor produces malignant cells that circulate when the body is asleep.
Cells that leave the tumor overnight are also more likely to metastasize than cells that leave the tumor during the day because they divide more rapidly.
“Our study shows that the release of circulating cancer cells from the original tumor is regulated by hormones such as melatonin that determine the daytime and nighttime rhythms,” added Zoi Diamantopoulou.
In addition, this study shows that the time a tumor or blood sample is taken for diagnosis can influence the conclusions of oncologists.
In this sense, according to the Swiss Center, it was a coincidence that the investigators were first put on the right track.
Scientists were surprised that the levels of cancer cells in samples taken at different times of the day were very different.
“In our opinion, these results may indicate that medical professionals need to systematically record the time to perform a biopsy,” Aceto emphasized, “data. It really helps to make it comparable. “
The next step for researchers is to find out how these findings can be incorporated into existing cancer treatments to optimize treatment.
Aceto wants to investigate whether different types of cancer work like breast cancer and whether existing treatments may be more successful if patients are treated at different times. I am.