Extracellular vesicles (EVs) are taking their place as potential biomarkers in the field of liquid biopsy. In this study, EVs were isolated from plasma samples of 31 patients with colorectal cancer and melanoma via differential centrifugation and Droplet Digital™ PCR (Bio-Rad, CA, USA) was used to profile BRAF V600E/K, KRAS G12A/C/D/V and KRAS G13D mutations from EV-derived cDNA. The concordance rates with corresponding tissue were 54% and 44% in the colorectal cancer and melanoma cohort, respectively. Two patients displayed mutations in EVs not previously detected in tissue as evidence for emerging molecular resistance to anti-EGFR and BRAF/MEK inhibitor therapy prior to radiological evidence of tumor progression. We concluded that EV-derived nucleic acids may provide clinically relevant diagnostic information and mirror evolution of the disease.
Keywords: colorectal cancer; ddPCR; exosomes; extracellular vesicles; liquid biopsy; melanoma.