The metastatic spread of cancer is achieved by the dissemination of circulating tumor cells (CTCs) in the blood. To date, cancer research has not paid much attention to the question of when tumors shed such CTCs. Researchers previously assumed that tumors release CTCs continuously. However, a new study by our partners at ETH Zurich, the University Hospital Basel, and the University of Basel has now come to a surprising conclusion: CTCs that later form metastasis mainly arise during the sleep phase of the affected individuals. The results of the study have just been published in the journal Nature.
“When the affected person is asleep, the tumor awakens,” summarises the B2B partner and study leader Nicola Aceto, Professor of Molecular Oncology at ETH Zurich. During the study, which included 30 female cancer patients and mouse models, Prof. Aceto’s team found that the tumor generates more circulating cells when the organism is asleep. Cells that leave the tumor at night also divide more quickly and therefore have a higher potential to form metastases, compared to circulating cells that leave the tumor during the day.
“Our research shows that the escape of circulating cancer cells from the original tumor is controlled by hormones such as melatonin, which determine our rhythms of day and night,” says Zoi Diamantopoulou, the study’s lead author and a postdoctoral researcher at ETH Zurich.
The researchers’ next step will be to figure out how these findings can be incorporated into existing cancer treatments to optimize therapies. As part of further studies with patients, ETH Professor Nicola Aceto wants to investigate whether different types of cancer behave similarly to breast cancer and whether existing therapies can be more successful if patients are treated at different times.
Reference: Diamantopoulou Z, Castro-Giner F, Schwab FD, et al. The metastatic spread of breast cancer accelerates during sleep. Nature. 2022:1-7. doi: 10.1038/s41586-022-04875-y