It’s So Rare, Scientists Have Only Seen It Four Times
What if we told you there was a type of cancer that could actually spread from one living creature to another?
It sounds like the plot of a sci-fi movie, but it’s a real discovery. Scientists have identified a rare transmissible cancer in freshwater fish, making it only the fourth known transmissible cancer ever found. Researchers studying brown bullhead catfish discovered the disease wasn’t developing separately in each fish. Instead, living cancer cells were being passed directly between them, allowing the cancer to spread in an incredibly unusual way.

Should We Be Worried?
Thankfully, the answer is no. Experts say there’s no evidence this cancer can spread to humans, and transmissible cancers remain exceptionally rare. Before this discovery, they’d only ever been found in Tasmanian devils, dogs and a handful of shellfish species. That makes this latest finding the first known case in a freshwater fish.
Why This Discovery Matters
While there’s no danger to people, scientists believe this rare cancer could help unlock some of medicine’s biggest mysteries. By studying how these cancer cells survive, spread and avoid the immune system, researchers hope to gain valuable insights into how cancer develops and evolves. It’s a fascinating breakthrough that shows there’s still plenty we don’t know about the natural world, and discoveries like this could one day help shape future cancer research.

