Mean circulating GDF-15 levels have been suggested to be higher in patients with pancreatic ductal adenocarcinoma, as 1731 pg/mL [23], 2428 [24], 7694.58 [1] and 2990.2 (this study), compared to patients with colorectal adenocarcinoma (CRC) (1371.0 pg/mL [23] and 2030 pg/mL [25]), non-small-cell lung carcinoma (mean, 1258.0 pg/mL [23] and median, 828.8–2000 pg/mL [34,35]), and gastric adenocarcinoma (1154.0 pg/mL [23]). Here, GDF15 is linked to pancreatic ductal adenocarcinoma.