Abstract

Point-of-Care System for Cancer Diagnostics and Therapy Monitoring

Michael Heller, Distinguished Scientist - Knight Cancer Institute, Center for Cancer Early Detection and Research (CEDAR), Oregon Health & Science University (OHSU)

Point of care (POC) devices for cancer and other molecular diagnostics still present considerable challenges. Cell free (cf) DNA and exosomal RNA and proteins are now regarded as important biomarkers for liquid biopsy cancer diagnostics, therapy monitoring and hold promise for early cancer detection. Until recently, the isolation of these biomarkers from patient samples required relatively complex, time consuming and expensive procedures which greatly limits their use for point of care (POC) cancer diagnostic applications. Now new AC electrokinetic (ACE) device (Biological Dynamics, La Jolla, CA) allow specific fluorescent dyes to be used first to simultaneously detect the different biomarker levels directly on the chip (in-situ). In a subsequent step, immunofluorescent analysis can be carried out to identify specific protein biomarkers on the exosomes. Finally, the cf-DNA and RNA (mRNAs and miRNAs release from the exosomes) can be eluted from the chip, and PCR, RT-PCR and sequencing analysis carried out to identify the cancer-related point mutations and other polymorphisms, as well as to further verify the tissue origin of the biomarkers. In the case of glioblastoma exosomes isolated from plasma, exosome-specific surface and interior proteins CD63 and TSG101 could be detected by immunofluorescence, and mutated EGFRvlll mRNA was detected by RT-PCR. Exosomal related protein biomarker Glypican-1 could be isolated from pancreatic cancer patient plasma samples by ACE and then detected on-chip by immunofluorescence, and Kras mutations detected in the eluted cf-DNA. Similar results are being obtained for prostate, breast, lung and brain cancer, as well as for TBI patient samples. Thus, ACE technology represents a powerful new minimally invasive technology for cancer diagnostics that is particularly well suited for the rapid isolation of cell free nucleic acid and exosome biomarkers. The technology is setting the stage for seamless sample to answer POC liquid biopsy diagnostics, cancer patient therapy monitoring and ultimately for early disease detection.