1B-O1-1605 PDF
Quantitation of putative colorectal cancer biomarker candidates in serum extracellular vesicles by targeted proteomics
At the moment, there is no sensitive clinical test for detecting early-stage colorectal cancer (CRC). Target proteomics has enabled high-throughput verification of hundreds of biomarker candidate proteins. In this study, we aimed to verify previously reported CRC biomarker candidate proteins in serum extracellular vesicles (EVs) of CRC patients by selected/multiple reaction monitoring. List of CRC biomarker candidate proteins was obtained from a PubMed from 2003 to 2014. A total of 723 previously reported CRC biomarker candidate proteins that are functionally correlated with CRC were verified from CRC patient sera in extracellular vesicles. Of these, 356 proteins were quantified, and 37 peptides (22 proteins) showed significant differences in the serum EVs between healthy controls and CRC patients, with or without metastasis (n=77). These peptides were evaluated as single or multiple markers. Four single peptides and 8 combinations of peptides showed AUC>0.9 to discriminate healthy control and CRC patient. Furthermore, sensitivities of three peptides for detection of stage 2 CRC were >80% when specificity was set as 100%, which greatly exceeds the sensitivity of CEA. These peptides are promising biomarkers for early detection of CRC. I would like to discuss how to apply these biomarkers for clinical examination and societal implementation.