Resection specimens containing adenocarcinoma (n = 17), intraductal papillary mucinous neoplasms (n = 11), and nonneoplastic tissues (n = 15) were evaluated for miR-21, miR-221, miR-100, miR-155, and miR-181b expression by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), and a subset of carcinomas and intraductal papillary mucinous neoplasms was analyzed with miRNA microarrays.
Four miRNAs (miR-155, miR-25, miR-495 and miR-7g) were expressed differently among these tumors. miR-155 was upregulated only in EGFR/KRAS-negative group, miR-25 was upregulated only in EGFR-positive group and miR-495 was upregulated only in KRAS-positive adenocarcinomas.