A research team at the University of Marburg has developed a method that can be used to gently and precisely monitor tumor growth in mouse models. The highlight: Instead of stressful imaging techniques, the scientists measure secreted luciferases – luminescent enzymes – directly in the animals’ blood. The concentration of these enzymes reflects the tumor burden and allows for continuous tracking over weeks or months.

The method consistently follows the 3R principle (Replace, Reduce, Refine): It reduces stress and anesthesia (Refine), reduces the number of animals required (Reduce) and can be combined with cell cultures (Replace). Tumor cells are labeled with different luciferases, so that several tumor types can be comparatively examined in an animal – even in internal organs such as the lungs or pancreas.

The research group led by Prof. Dr. Thorsten Stiewe (Institute of Molecular Oncology) has optimized the procedure over more than ten years. Detailed instructions have now been published in Nature Protocols (DOI: 10.1038/s41596-025-01315-9). The first authors are Dr. Nastasja Merle and Imke Bullwinkel.

“The method presented here impressively shows that excellent research and high ethical standards are not a contradiction,” says the Vice President of Research at the University of Marburg, Prof. Dr. Gert Bange. “By reducing stress on the animals and at the same time obtaining meaningful data, this work provides important impetus for responsible biomedical research.”

The method is to be widely used to make preclinical studies more comparable and animal-friendly – a step towards more efficient development of new cancer drugs.

Original Paper:

Secreted luciferases as a minimally invasive 3R-compliant tool for accurate monitoring of tumor burden | Nature Protocols

Editor: X-Press Journalistenbüro GbR

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