Using "avatar" mice, the Mayo Clinic's Breast Cancer Genome Guided Therapy Study, called BEAUTY, aims to develop a personalized approach to neoadjuvant chemotherapy treatment. Researchers kept tumor tissue samples from 200 early-stage, high-risk breast cancer patients — taken both before and after chemotherapy treatment — alive using cell lines that they later implanted into immune-compromised mice. These xenografted mice will enable the Mayo team to study how chemotherapy affects individual patient tumors in order to pinpoint the best treatments, without subjecting the patient to the usual trial-and-error process of determining the right drug.
Should the BEAUTY study prove fruitful, the researchers hope that their mouse avatar model could be applied to a number of other malignancies for which neoadjuvant therapy is used. "The [Mayo Clinic's] Center for Individualized Medicine is tasked to incorporate individualized medicine into the care of our patients and will be working very closely with the [Mayo Clinic] Cancer Center to expand these studies and others like it into the clinical practice," says Matthew Goetz, associate professor of oncology and pharmacology at the Mayo Clinic.
Using avatar mice can be challenging for a number of reasons, and housing the animals can be costly. Determining which tumors can be successfully xenografted has been the greatest challenge, though preliminary data suggest that the most treatment-resistant tumors are more likely to engraft. "That is likely to be an advantage, given the population of patients we are treating," Goetz says.
Another challenge, he adds, is "ensuring fidelity between the primary tumor and the patient-derived tumor growing in the mouse."
The Mayo Clinic team is also currently looking at the best way to collaborate with drug companies to use data generated from this study to further optimize drug selection and development for use in high-risk cases.