Spreading cancer caught on film
The way in which every single cancer cell spreads around the body has been captured in videos by a team in Japan.
The normal body tissues show up as green, while the cancer comes out as intense red spots.
The team, at the University of Tokyo and the RIKEN Quantitative Biology Center, says the technology will help explain the deadly process.
The research is on mice so far, but it is hoped the method could one day help with treatment too.
The spread of cancer around the body is a crucial moment called metastasis.
Before a cancer spreads it is easier to contain and cure, afterwards it is incredibly difficult.
The tumour itself has to evolve so bits of it are able to break free, survive travelling in the blood stream and invade new tissues.