Blood-derived non-extracellular vesicle proteins as potential biomarkers for the diagnosis of early ER+ breast cancer and detection of lymph node involvement

Extracellular vesicles (EV’s) are membrane surrounded structures released by different cell types and are emerging as potential therapeutic and diagnostic targets in cancer. In the present study, plasma samples derived from 7 patients with metastatic and non-metastatic ER+ (estrogen receptor positive) breast cancer (BC) were collected and their respective (EVs) isolated and the protein content analyzed by mass spectrometry and FunRich analysis. Two putative plasma biomarkers (absent in healthy controls samples) were identified which could be used to detect early ER+ breast cancer and for those with lymph node (LN) involvement However, given the current limitations of the EV isolation method used, it is possible that these biomarkers did not originate from EVs and may represent blood-derived extracellular proteins.  Further work in a larger patient cohort is warranted to confirm these findings and examine the diagnostic potential of these biomarkers.