Researchers could observe cancer metastasis processes at a single-cell level through a technology that makes mouse bodies transparent.

The team was led by systems pharmacologist Hiroki Ueda and molecular pathologist Kohei Miyazono, both professors at the University of Tokyo. They said the technology could be used to help verify the therapeutic effects of anti-cancer agents and shed light on the mechanisms of cancer metastasis.

“The applicability of our technology is not limited to cancer,” Ueda said. “It could be useful for regenerative medicine, and it could also help study autoimmune diseases and other illnesses for which therapies remain underdeveloped or mechanisms have yet to be elucidated.”

Ueda and co-workers in 2014 successfully made entire mouse bodies transparent by using a chemical reagent that removes lipids and blood pigments.

They used an improved reagent in the latest study to achieve a higher transparency.

Before the mouse bodies were made transparent, they received transplanted kidney cancer cells that had been tweaked to glow red. The use of a special microscope allowed the researchers to observe how cancer cells metastasized to the lung, liver and other organs.

The procedure also worked with breast, lung, melanoma skin and other cancers.

The research results were published online July 6 in Cell Reports, a U.S. scientific journal.