Unexpectedly, the metastasis showed significant > 20–70 fold upregulation in both insulin-expressing cancer cell populations of several marker genes typically associated with the exocrine pancreas, including CLPS, ENSCAFG00000014481 (PRSS2), ENSCAFG00000003818 (PRSS), and CTRC. The significance of this is not clear, but these genes might be important markers of metastatic transformation, invasion or associated with de-differentiation in canine insulinoma, in addition to their reported roles in pancreatitis [21, 22]. This evidence concerns the gene CLPS and pancreatic insulinoma.