Early-stage pancreatic cancer cells can be illuminated in live mice with infrared light.

Pancreatic cancer is one of the deadliest of human cancers, and is often diagnosed only in the later stages of the disease. Dieter Saur at the Technical University of Munich, Germany, and his colleagues found that pancreatic cancer cells in mice express higher levels of certain cathepsin proteins — which break down other proteins — than healthy cells do. The researchers injected a mouse model of the disease with an agent that emits near-infrared light when activated by these proteins. They then inserted a fluorescence-laser-microscopy probe into the animals to detect the light. The pattern of light emission differed between early- and late-stage cancer cells, and the researchers were even able to identify premalignant cells.

If this probe works in humans, it could be used for early screening of at-risk individuals, say the authors.

Proc. Natl Acad. Sci. USA doi:10.1073/pnas.1100890108 (2011)