Finally, we evaluated GPC1 mRNA levels in human serum EVs from PDAC patients at stage I–II (n = 86), stage III–IV (n = 32), benign pancreatic disease (BPD, n = 15; patients with pancreatitis), and healthy donors (n = 60) in a discovery study (Supplementary Table 3). Here, GPC1 is linked to pancreatitis.