Chicken eggs could provide low-cost opportunities for cancer imaging research

In a paper published in npj Imaging, King's researchers have assessed the use of fertilized chicken eggs as an alternative model that can resolve both ethical and economic issues for preclinical cancer research.

The use of animal models in cancer research is a major contributor to the clinical development of drugs and diagnostic imaging. However, while invaluable tools, the current standard of using mouse models to recreate diseases is expensive, time-intensive, and complicated by both variable tumor take rates and the associated welfare considerations.

Fertilized chicken eggs contain a highly vascularized membrane, known as the chicken chorioallantoic membrane (CAM), which can provide an ideal environment for tumor growth and study, but to date, relatively few studies have used chick CAM to evaluate novel radiopharmaceuticals.

"This work supports the case for the use of chick CAM as a more sustainable, low-cost substitute to mouse models of cancer, with results showing that it is possible to cultivate tumors for imaging in 7 days using this approach. 12 fertilized eggs cost just £45, with zero maintenance costs—a 97% saving compared to standard mouse xenografts."

"But more importantly, these eggs provided exquisite tumor images that allowed us to assess the delivery of tumor-targeting drugs and the effects of radiation therapy. I initially thought all we'd produce is scrambled eggs, but this model was robust and versatile," says Dr. Tim Witney, Reader in Molecular Imaging at the School of Biomedical Engineering & Imaging Sciences.

"Testing new imaging agents in cancer cells in culture is a useful first step, but it only gets us so far—it's hard to know how an imaging agent that works in a petri dish would work in the body. Progressing to mouse models of cancer is extremely expensive and time-consuming, and is heavily regulated (for very good reason)."

"Growing tumors in a chicken egg is an interesting intermediate step that could accelerate imaging agent development at a fraction of the cost. I'm very pleased to see this work published—the endless egg puns have been no yolk," says Dr. Richard Southworth, Reader in Cardiac Molecular Imaging.

To be widely adopted as a model for radiopharmaceutical research, a straightforward protocol for the use of chick CAM must be established. To this end, the researchers used direct comparison studies to test the viability of the chick CAM approach against mouse models and demonstrated its potential to accomplish novel radiotracer development and assess treatment responses in test subjects more quickly.