MRI with a specific isotope 19 allows in vivo tracking of tumor-associated macrophages in brain cancers

Prof.Johanna Joyce’s laboratory is focused on exploring and exploiting the tumor microenvironment (TME) in different cancers. They investigate the cellular composition of primary and metastatic brain tumors, and are revealing the biological roles of both cancerous and non-cancerous cell types in regulating tumor development, growth and response to therapies. Tumor-associated macrophages (TAMs) are one of the most abundant non-malignant cell types, with key functions in the TME, including in primary brain tumors.

Previous studies from the Joyce Lab have identified the multifaceted roles of TAMs in the TME and discovered their critical importance in disease management. While macrophage functions and content have been studied with various approaches in experimental models of glioma, the non-invasive and longitudinal monitoring of these cells over time has proven challenging.

In this study, the Joyce lab and their collaborators, led by PhD student Davide Croci, addressed this challenge – and discovered that 19F MRI can be used to visualize TAMs in vivo by injecting perfluorocarbon-containing nanoparticles. Notably, they were able to track different macrophage populations over time, including in response to radiotherapy, and thereby revealed distinct cellular niches within the recurrent TME.

This research* was conducted in collaboration with Dr Ruud van Heeswijk of the Lausanne University Hospital’s Service of diagnostic and interventional radiology.

*Multispectral fluorine-19 MRI enables longitudinal and non-invasive monitoring of tumor-associated macrophages