We further detected the protein level of ISG15 in the TMA containing PDAC and normal adjacent pancreatic tissues (Figure 7A) and found that staining for ISG15 was strong in PDAC tumor cells (Figure 7A, top), whereas in noncancerous tissues, the staining was weak or undetectable, except in islet cells that showed positive staining (Figure 7A, bottom). This evidence concerns the gene ISG15 and neoplasm.