On the basis of the LFQ results (Figure S4), relevant proteins (pivotal for CRC biology, metastasis, and EV biogenesis) were selected to confirm their presence in CTC-derived EVs via an MRM assay: CD9, CD81, CD44, CLD3, CTNNB1, EPCAM, ITGA6, ITGB1, ITGB4, PDCD6IP, RAP2B, SDCP, SYNGR2, ADAM10, CAB39, and H2AFY. This evidence concerns the gene CD81 and colorectal carcinoma.