Pancreatic+Cancer

Pancreatic cancer is defined as a "malignant neoplasm" that arises from the cells of pancreatic tissue. This unrestricted growth is characteristic of the mutated cells forming tumors in the pancreas, and in other organs of the body as in other forms of cancer. The most common type of pancreatic cancer is pancreatic ductal adenocarcinoma (PDAC) which makes up approximately 90% of all PC cases (Cellular Classification 2014). PDAC is defined as an exocrine tumor type and affects the enzyme releasing part of the pancreas's job. Other forms of malignant pancreatic cancer includes acinar cell carcinoma, adenosquamous carcinomas, and cystadenocarcinomas, to name a few. We will focus primarily on this form of the cancer because of the prevalence of PDAC in the population worldwide and the abundance of information we have both on the disease itself and from studies done on PDAC cells. Pancreatic intraepithelial neoplasia (PanIN) is the precursor to PC and can slowly progress over many years before developing into fully invasive PDAC (Figure 1). PanIN lesions are defined as "flat, noninvasive epithelial neoplasms that are usually < 5 mm and confined to pancreatic ducts" (Pancreatic Intraepihelial Neoplasia 2014) These lesions are then divided into three grades according to degree of cytological and architectural atypia, or how structurally abnormal they are. The grades then correspond to "minimal-" = 1, "moderate-" = 2, and "marked-atypia" = 3 with a PanIN 3 lesion being carcinoma //in situ// (Pancreatic Intraepithelial Neoplasia 2014). Once a PanIN lesion progresses to the third grade, it has the potential to develop into PDAC. It is here, in this progression from benign to malignant where we want to halt cancer cells.

(Costello and Evans, 2012)


 * Figure 1.** Progression of normal pancreatic ductal epithelial cells to PanIN lesions to PDAC.

The pancreas is a glandular organ involved in both the endocrine and digestive system. It's primary role as an endocrine gland is to produce several hormones needed in the body, including insulin, glucagon, somatostatin, and pancreatic polypeptide which circulate in the blood. The pancreas also functions as an exocrine gland, releasing pancreatic juices which contains digestive enzymes meant to assist in digestion and the absorption of nutrients in the small intestine (Karolinska Institutet 2011). The pancreas is situated in the dorsal portion of the upper abdominal quadrants, behind the stomach and tucked in with the small intestine (Figure 2). This position makes it particularly difficult to detect early stages of pancreatic cancer.

(University of Chicago Medicine, 2014)


 * Figure 2.** Anatomy of the pancreas and surrounding organs in the human body.

The part of the pancreas that secretes hormones is made up thousands of cell clusters called the Islets of Langerhans (Karolinska Institutet 2011). Four main cell types exist: alpha cells, which secrete glucagon, beta cells, which secrete insulin, delta cells, which secrete somatostatin, and PP or gamma cells, which secrete pancreatic polypeptides (Karolinska Institutet 2011). Because of the vital processes carried out by the pancreas, cancer to these cells can be devastating, and the lack of effective treatment has taken its toll on the PC mortality rate.