High levels of serum glypican‐1 indicate poor prognosis in pancreatic ductal adenocarcinoma

Carbohydrate antigen 19‐9 (CA19‐9) fails to demonstrate the predictive value for early detection pancreatic ductal adenocarcinoma (PDAC). Glypican‐1 (GPC1+) exosomes may serve as a noninvasive diagnostic tool to detect early stages of PDAC. Therefore, it is necessary to explore the serum GPC1 levels and determine whether serum GPC1 serves as a novel biomarker for PDAC patients. Blood samples were collected from 156 patients with PDAC, 199 non‐cancer controls, and 240 patients with other cancers. Serological levels of GPC1 were examined by enzyme‐linked immunosorbent assay (ELISA). Finally, a 5‐year follow‐up was monitored to evaluate the correlation between serum GPC1 levels and overall survival in 156 patients with PDAC. The results suggested that levels of serum GPC1 and CA19‐9 were higher in PDAC patients than that of controls (P < 0.05). Serum GPC1 levels in PDAC were different from those in gallbladder carcinoma (P < 0.001), colorectal carcinoma (P < 0.001), gastric carcinoma (P < 0.001), and prostate cancer (P < 0.001), but not hepatocellular carcinoma (P = 0.395) and cholangiocarcinoma (P = 0.724). Receiver operating characteristic curve (ROC) analysis showed that serum CA19‐9 was significantly better than serum GPC1 in distinguishing PDAC patients from the controls (AUC, 95% CI: 0.908, 0.868‐0.947 vs 0.795, 0.749‐0.841, respectively). The serum GPC1 cannot be used as a serum diagnostic biomarker for PDAC patients. The level of serum GPC1 decreased 2 days after surgery (P = 0.001), which were not different from serum GPC1 levels in healthy control (P = 0.381). The overall survival rate was shorter in patients with high levels of serum GPC1 compared to those with low levels of serum GPC1 (log‐rank = 5.16, P = 0.023). Taken together, the results indicate that high levels of serum GPC1 predict poor prognosis in PDAC patients. Serum GPC1 may be a prognosis factor for PDAC patients.