Abstract

Exosomes, Advancing Liquid Biopsy Diagnostics

Johan Skog, Chief Scientific Officer, Exosome Diagnostics Inc

The field of liquid biopsy has gained enormous interest in recent years.  An important goal of personalized medicine has been being able to detect tumor derived genetic profiles and tracking the evolution of tumor mutations over time.  Utilizing cell free tumor DNA (ctDNA) for detection of mutations in plasma has shown some promise in late stage cancer patients, but can only be used to track genetic changes. A more complete picture can be seen by combining the mutations in ctDNA with the mutations and RNA profiles from exosomes. We have validated and launched the world’s first clinical tests using exosomal RNA (exoRNA). We have also developed a single step isolation platform for exoRNA and ctDNA from biofluids, which increases the available mutant copies from the tumor available for analysis.  In a blinded head to head analysis, this platform had better sensitivity when compared to ctDNA alone. Exosomes are especially interesting because they are released as an active process from not only cancer cells, but also other cells, such as tumor stroma and immune cells. This enables us to access RNA profiles when monitoring response to more complex processes, such as immunotherapy response, where monitoring mutations may not be sufficient.