CCL15 and undifferentiated pancreatic carcinoma: Among all types of pancreatic cancer, including pancreatic adenocarcinoma, pancreatic neuroendocrine tumors, and undifferentiated pancreatic carcinoma found in the database, which were extracted from 596 patient samples of three PDAC studies, it showed that CCL15 gene amplification was only detected in pancreatic adenocarcinoma (Figure S1A).