Identification and analysis of precursors to invasive pancreatic cancer.
ABSTRACT Precursor lesions of pancreatic cancer have been recognized about a century ago. The development of a consistent reproducible nomenclature and classification system for these lesions has been a major advance in the study of these noninvasive precursors. Pancreatic intraepithelial neoplasia (PanIN) as microscopic precursor lesions can be distinguished from mucinous cystic neoplasms (MCNs) and intraductal papillary mucinous neoplasms (IPMN) that are cystic and can often be recognized on imaging. Since precursor lesions harbor the unique chance to treat a patient before a fatal pancreatic cancer can arise a molecular characterization is essential to understand the biology and to find diagnostic and therapeutic targets to fight this disease of near uniform lethality. In order to study precursor lesions on a molecular level a meticulous isolation of the neoplastic cells is inevitable. We present the salient histopathologic and molecular features of precursor lesions of pancreatic cancer as well as methods that have proved to be useful within experimental studies.
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ABSTRACT: The monitoring of pancreatic ductal adenocarcinoma (PDAC) in high-risk populations is essential. Cathepsin E (CTSE) is specifically and highly expressed in PDAC and pancreatic intraepithelial neoplasias (PanINs), and its expression gradually increases along with disease progression. In this study, we first established an in situ 7,12-dimethyl-1,2-benzanthracene (DMBA)-induced rat model for PanINs and PDAC and then confirmed that tumorigenesis properties in this model were consistent with those of human PDAC in that CTSE expression gradually increased with tumor development using histology and immunohistochemistry. Then, using in vivo imaging of heterotopically implanted tumors generated from CTSE- overexpressing cells (PANC-1-CTSE) in nude mice and in vitro imaging of PanINs and PDAC in DMBA-induced rats, the specificity of the synthesized CTSE-activatable probe was verified. Quantitative determination identified that the fluorescence signal ratio of pancreatic tumor to normal pancreas gradually increased in association with progressive pathological grades, with the exception of no significant difference between PanIN-II and PanIN-III grades. Finally, we monitored pancreatic carcinogenesis in vivo using confocal laser endomicroscopy (CLE) in combination with the CTSE-activatable probe. A prospective double-blind control study was performed to evaluate the accuracy of this method in diagnosing PDAC and PanINs of all grades (>82.7%). This allowed us to establish effective diagnostic criteria for CLE in PDAC and PanINs to facilitate the monitoring of PDAC in high-risk populations.PLoS ONE 09/2014; 9(9):e106566. · 3.53 Impact Factor