Faculty Bibliography

Accurate staging of pancreatic adenocarcinoma is a crucial step in determining the appropriate therapeutic approach to pancreatic cancer and to maximizing life expectancy. Despite the availability of high-quality abdominal imaging, the use of multi-modality imaging and of diagnostic laparoscopy, a portion of surgically explored patients fail to undergo resection secondary to metastatic disease. This review is an update from the 2012 American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium of new developments in the staging of localized pancreatic adenocarcinoma. (Abstracts #168, #177, and #212).

Intraductal papillary mucinous neoplasms (IPMNs) are a heterogeneous group of mucin producing cystic tumors that involve the main pancreatic duct and/or branch ducts and may be associated with invasive carcinoma. Predicting the risk of malignant transformation of an IPMN lesion can be challenging. The Sendai criteria, based in large part on radiographic imaging features, help guide surgical intervention based on the stratification of cysts into high and low risk lesions for malignancy. Invasive carcinoma may develop in the index IPMN lesion or in a separate site within the pancreas, supporting the concept of a field defect in IPMN tumorigenesis. This stresses the importance of evaluation of the entire pancreas upon diagnosis of IPMN and continued surveillance of the residual pancreas following resection. Herein, the authors summarize the data presented at the 2012 ASCO Gastrointestinal Cancers Symposium regarding prevalence and site of invasive carcinoma detected in patients undergoing surveillance for IPMN (Abstract #152).

BACKGROUND: The receptor for advanced glycation end-products (RAGE) is implicated in pancreatic tumorigenesis. Activating Kras mutations and p16 inactivation are genetic abnormalities most commonly detected as pancreatic ductal epithelium progresses from intraepithelial neoplasia (PanIN) to adenocarcinoma (PDAC). OBJECTIVE: The aim of this study was to evaluate the effect of RAGE (or AGER) deletion on the development of PanIN and PDAC in conditional Kras ( G12D ) mice. MATERIALS AND METHODS: Pdx1-Cre; LSL-Kras ( G12D/+) mice were crossed with RAGE (-/-) mice to generate Pdx1-Cre; LSL-Kras ( G12D/+) ; RAGE (-/-) mice. Pdx1-Cre; LSL-Kras ( G12D/+); p16 ( Ink4a-/-) mice were crossed with RAGE (-/-) mice to generate Pdx1-Cre; LSL-Kras ( G12D/+); p16 ( Ink4a-/-); RAGE (-/-) mice. Pancreatic ducts were scored and compared to the relevant RAGE (+/+) controls. RESULTS: At 16 weeks of age, Pdx1-Cre; LSL-Kras ( G12D/+); RAGE (-/-) mice had significantly fewer high-grade PanIN lesions than Pdx1-Cre; LSL-Kras ( G12D/+); RAGE (+/+) controls. At 12 weeks of age, none of the Pdx1-Cre; LSL-Kras ( G12D/+); p16 ( Ink4a-/-); RAGE (-/-) mice had PDAC compared to a 45.5% incidence of PDAC in Pdx1-Cre; LSL-Kras ( G12D/+); p16 ( Ink4a-/-); RAGE (+/+) controls. Finally, Pdx1-Cre; LSL-Kras ( G12D/+); p16 ( Ink4a-/-); RAGE (-/-) mice also displayed markedly longer median survival. CONCLUSION: Loss of RAGE function inhibited the development of PanIN and progression to PDAC and significantly prolonged survival in these mouse models. Further work is needed to target the ligand-RAGE axis for possible early intervention and prophylaxis in patients at risk for developing pancreatic cancer