According
to a study, breast cancer spreads at night
According
to the World Health Organization, one of the most common types of cancer is
breast cancer (WHO). Throughout 2.3 million people around the world get the
illness every year. Patients typically benefit from therapy if breast cancer is
found in its early stages by doctors. However, if cancer has already spread,
things can be challenging. When circulating cancer cells split out from the
primary tumour and migrate through blood arteries to different organs, this
process is known as metastasis.
When
tumours lose metastatic cells has not received much attention in cancer
research yet. Previous research thought that tumours continuously release these
cells. However, a recent study by academics from the University of Basel,
University Hospital Basel, and ETH Zurich has discovered a startling finding:
cancer cells that circulate in the body and eventually metastasize primarily
appear during the sleep phase of those who are afflicted.
The
circadian cycle regulates hormones that control metastasis
Nicola
Aceto, professor of molecular oncology, summarises the phenomenon as "the
tumour awakens when the affected person is asleep." The researchers
discovered throughout their investigation, which involved 30 female cancer
patients and mice models, that the tumour produces more circulating cells when
the body is sleeping. In addition to dividing more quickly, cells that leave
the tumour at night have a higher propensity to metastasize than circulating
cells that do so during the day.
Our
research "demonstrates that hormones like melatonin, which regulate our
rhythms of day and night, are crucial for limiting the escape of circulating
cancer cells from the original tumour," says lead author and postdoctoral
researcher Zoi Diamantopoulou.
Modifying
treatments for the tumour
The
study also suggests that the timing of tumour or blood samples for diagnosis
may affect oncologists' conclusions. The researchers were initially pointed in
the right direction by an unintentional discovery along these lines. Aceto says
with a smile, some of my coworkers work early in the morning or late in the
evening; occasionally they'll even analyse blood at odd hours. The researchers
were surprised to find that there were significantly different levels of
circulating cancer cells in samples taken at different times of the day.
Another
indicator was the very large proportion of cancer cells in mice's blood
compared to that in people. The cause was that mice, who are nocturnal
creatures, usually slept during the day when investigators would collect their
samples.
These
findings, according to Aceto, may point to the need for healthcare providers to
systematically record the time at which they do biopsies. Making the data truly
comparable might be helpful.
The
researchers' next task will be to determine how to best apply these discoveries
to currently used cancer therapy. ETH Professor Nicola Aceto plans to do
additional research with patients to see whether other cancers are similar to
breast cancer and whether the timing of treatment for patients can improve the
effectiveness of current medications.