This content is Subscriber-Exclusive
You must have a National Geographic subscription to explore this article.
Breast cancer spreads more aggressively during sleep
Many more cancerous cells circulate in the blood at night, suggesting that time of day could play a role in diagnosis and treatment.
This electron microscope scan shows a circulating tumor cell (CTC) cluster seen within the filters of a microfluidic device used to process blood samples. Every cell of the cluster comes from the same patient. This metastatic cell cluster, which is smaller than a full-stop in a magazine, floats through the blood and settles in healthy tissues, allowing the cancer to spread.
Read This Next
Go Further
Animals
- Fireflies are vanishing—but you can help protect themFireflies are vanishing—but you can help protect them
- Could this simple plan save Africa's most mysterious cat?Could this simple plan save Africa's most mysterious cat?
- This ray is vanishing from our oceans—and being made into jewelryThis ray is vanishing from our oceans—and being made into jewelry
- Why 4 dead California sea otters have scientists so alarmedWhy 4 dead California sea otters have scientists so alarmed
- SeaWorld violated the Animal Welfare Act. Why is it still open?SeaWorld violated the Animal Welfare Act. Why is it still open?
- Vengeance or playtime? Why orcas are attacking boatsVengeance or playtime? Why orcas are attacking boats
Environment
- Is banning fishing bad for fishermen? Not in this marine reserveIs banning fishing bad for fishermen? Not in this marine reserve
- Dust storms are getting worse—here’s why they’re so destructiveDust storms are getting worse—here’s why they’re so destructive
- Japan poised to release nuclear wastewater into the PacificJapan poised to release nuclear wastewater into the Pacific
History & Culture
- They were seeking a mythical oasis—and found a Stone Age surpriseThey were seeking a mythical oasis—and found a Stone Age surprise
- Why do we celebrate Memorial Day? A brief history of the holidayWhy do we celebrate Memorial Day? A brief history of the holiday
Science
- You can detox your uterus—and other myths about PCOS, debunkedYou can detox your uterus—and other myths about PCOS, debunked
- Raging river and frost-tipped dunes reveal watery history on MarsRaging river and frost-tipped dunes reveal watery history on Mars
- The end of cervical cancer? It might be within reach.The end of cervical cancer? It might be within reach.
- How a poor gel manicure can lead to lifelong health issuesHow a poor gel manicure can lead to lifelong health issues
- Are you a stress eater? Here’s how to retrain your brain.Are you a stress eater? Here’s how to retrain your brain.
Travel
- Is America’s first wilderness area still wild at heart?Is America’s first wilderness area still wild at heart?
- A UK break in Falmouth, Cornwall's maritime boomtownA UK break in Falmouth, Cornwall's maritime boomtown
- An essential guide to the street art scene of Kaunas, Lithuania
- Paid Content for Advertiser
An essential guide to the street art scene of Kaunas, Lithuania - Canada's greatest natural wonders: what not to missCanada's greatest natural wonders: what not to miss