Britannica
Sources used in this answer
Where do most pancreatic cancers begin within the pancreas?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
pancreatic cancer
The human pancreas is composed of two main types of tissue: acinar cells and islets of Langerhans. The acinar cells produce digestive enzymes, which are secreted into tiny ducts that feed into the pancreatic duct. Islets of Langerhans are clusters of cells that secrete hormones such as insulin and glucagon directly into a capillary network, which also joins the pancreatic duct.
Most pancreatic cancers originate within the exocrine portion of the pancreas, which accounts for approximately 95 percent of cases. Specifically, these malignancies arise primarily from the organ's ductal system. The remaining 5 percent of cases develop from endocrine cells and are typically classified as neuroendocrine tumors or islet-cell cancers.12