Cancer is most deadly when cells from the tumor enter the bloodstream and move to new places in the body to metastasize.A study published in a scientific journal this Wednesday Nature We conclude that for people with breast cancer, these harmful cells, called circulating tumor cells, are more likely to transfer to the blood at night than during the day.
According to Nikola Aceto, an oncology biologist at the Federal Institute of Technology in Zurich and one of the authors of the study, the study shows that “the tumor awakens when the patient is asleep.” It is a “progress” in understanding metastasis. “And moving forward is good for the patient in the long run.”
The team began by noting that the level of circulating tumor cells in mice changed depending on the time of blood sampling. Based on this observation, blood was drawn from 30 breast cancer patients once at 4 am and once at 10 am.
Almost 80% of the circulating tumor cells found in the blood sample appeared in a collection made at 4 o’clock in the morning when the patient was still resting. “I was surprised because of the doctrine that tumors constantly circulate cells. But the data were very clear. Immediately after the surprise, we really started to get excited,” says Aceto. increase.
Breast cancer tumors were introduced into mice in addition to the samples performed to confirm obvious findings. This group found that levels of circulating tumor cells peaked during the day when mice were at rest. These animals are most active at night and tend to rest during the day.
In addition, they also collected circulating tumor cells and reinjected them while the mice were resting and active. This revealed that most of the cells that turned into new tumors were the cells that were collected when the mice were resting.
At the time, this revelation was “impressive,” said Chi Van Dang, an oncology biologist at Ludwig Cancer Research. Nature.. Levels of circulating tumor cells in the blood are measured in the diagnosis of progression in cancer patients, and this novelty indicates that “the time when a blood sample is taken can provide misleading information.” He points out.
As to why human breast cancer cells become more active at night, Aceto points out that this is probably due to a number of factors that still need to be investigated, but hormones may play a role.