Detection of Large Tumor-Derived Vesicles in Cancer

This technical report presents a study on the detection of large tumor-derived extracellular vesicles (tdEVs), specifically large oncosomes (LOs), in metastatic breast cancer patients. The report outlines the development of a RareCyte platform-based enumeration method for LOs and compares its efficacy against the established CellSearch platform. The study analyzed blood samples from 73 metastatic breast cancer patients, focusing on the detection of HER2 on LOs and correlating the results with tissue biopsy HER2 scores. The findings indicate that the RareCyte method detected a higher number of particles compared to the CellSearch method, particularly in HER2 negative cases. Furthermore, the LO HER2 status was found to correlate strongly with tissue biopsy HER2 scores. Statistical analyses demonstrated significant correlations between particle counts and overall survival outcomes, suggesting that LOs could serve as a valuable biomarker for liquid biopsy-based HER2 detection. The report concludes with a call for prospective studies to further evaluate the predictive capabilities of LO HER2 status for therapy response.