Gene expression changes associated with the progression of intraductal papillary mucinous neoplasms

The diagnosis of high-grade intraductal papillary mucinous neoplasm (IPMN) is difficult to distinguish from low-grade IPMN. The aim of this study was to identify potential markers for the discrimination of high-grade and invasive (HgInv) IPMN from low- and moderate-grade dysplasia IPMN. Laser capture microdissection was used to isolate distinct foci of low-grade, moderate-grade, high-grade, and invasive IPMN from paraffin-embedded archival tissue from 14 patients who underwent resection for IPMN. Most samples included multiple grades in the same specimen. Affymetrix Human Exon microarrays were used to compare low- and moderate-grade dysplasia IPMN with HgInv IPMN. Sixty-two genes were identified as showing significant changes in expression (P ≤ 0.05 and a 2-fold cutoff), including up-regulation of 41 in HgInv IPMN. Changes in gene expression are associated with biological processes related to malignant behavior including cell motion, cell proliferation, response to hypoxia, and epithelial-to-mesenchymal transition. In addition, altered signaling in several transforming growth factor β-related pathways was exhibited in the progression of IPMN to malignancy. This study identifies a set of genes associated with the progression of IPMN to malignancy. These genes are potential markers that could be used to identify IPMN requiring surgical resection.