Horrifying Video Shows How Cancer Spreads Through the Bodies of Mice

mouse cancer
Still from video showing the spontaneous metastasis of cancer. Hiroki R. Ueda et al.

One of the main reasons that cancer is so deadly is its spread from one part of the body to the other—and understanding how and why it happens is integral to improving treatments for the disease.

But following individual cancerous cells during this process is inherently difficult as they scatter around the whole body—and not all will develop new tumors.

Now scientists in Japan have developed a technique that allows them to observe how cancer spreads through the bodies of mice, a process known as metastasis.

Videos released by the team from the University of Tokyo and the RIKEN Quantitative Biology Center show cancer cells spreading in different parts of the body, including from the pancreas into the liver and through the abdomen, as well as within the lungs and brain.

Researchers describe the method in the journal Cell Reports, showing how they were able to image cancer at the single cell level by using chemicals that make the body and organs transparent. They combined this with current imaging techniques used to track cancer cells in order to watch them multiplying in different parts of the body, before travelling through the bloodstream to new areas.

As a result, they have been able to get a better view of the steps that take place during metastasis. While most cancer cells died in transit, those that arrived in new areas of the body did so by surfing through the bloodstream and entering new tissues through blood vessel walls.

"Most cancer cells are not so lucky and die during the trip," said co-corresponding author Kohei Miyazono. "But images obtained through the new method suggest that cells treated with TGF-beta, a protein that regulates cellular growth and differentiation in humans and is produced in increased quantities by some cancers, are far more likely to survive the journey and form malignant outposts."

This research should help scientists better understand how cancer spreads and they now plan to look more deeply into metastatic pathways. They also believe the technique could be used to look at the pathways of other diseases, saying this "analytical pipeline would have great potential for becoming a de facto standard for an in vivo therapeutic evaluation system for complex systemic diseases."

Co-corresponding author Hiroki Ueda added: "We believe that same strategy will be applicable to other biomedical studies such as autoimmunity and regenerative medicine, in which the single-cell events play crucial roles."