Journal of Gastrointestinal Surgery

, 12:2171

MicroRNA-21 is Overexpressed in Pancreatic Cancer and a Potential Predictor of Survival

  • Mary Dillhoff
  • James Liu
  • Wendy Frankel
  • Carlo Croce
  • Mark Bloomston
original paper

DOI: 10.1007/s11605-008-0584-x

Cite this article as:
Dillhoff, M., Liu, J., Frankel, W. et al. J Gastrointest Surg (2008) 12: 2171. doi:10.1007/s11605-008-0584-x

Abstract

Background

MicroRNAs are small (18–22 nucleotides) noncoding RNAs involved in posttranscriptional modification of many target genes. One of these, microRNA-21 (miR-21), has been shown to play a role in multiple hematologic and solid organ malignancies. We sought to determine the expression pattern of miR-21 in pancreatic cancers and its impact on clinicopathologic characteristics.

Methods

Eighty resected pancreatic cancer specimens were microdissected and tissue microarrays (TMA) created in duplicate. TMAs were also created for benign pancreas (N = 12) and chronic pancreatitis (N = 45). In situ hybridization (ISH) was undertaken utilizing locked nucleic acid probes for miR-21. RNA U6 and scrambled RNA served as positive and negative control, respectively. ISH was scored as 0 (absent), 1+ (faint/focal expression), or 2+ (strong expression). Kaplan–Meier survival curves were constructed and compared by log-rank analysis.

Results

MiR-21 expression was demonstrated in 63 (79%) pancreatic cancers (1+ in 49, 2+ in 14) compared to one of 12 (8%, p < 0.0001) benign pancreas and 12/45 (27%, p < 0.0001) chronic pancreatitis. None of the benign tissues demonstrated strong miR-21 expression. Although miR-21 expression did not correlate with tumor size, differentiation, nodal status, or T stage, strong miR-21 expression was predictive of poorer outcome compared to absent or faint/focal miR-21 expression in patients with node-negative disease (median 27.7 months vs. 15.2, p = 0.037). Nodal status was also predictive of survival (p = 0.029).

Conclusions

MicroRNA-21 is significantly overexpressed in pancreatic cancers as detected by in situ hybridization. Its strong expression predicts limited survival in patients with node-negative disease and may be an important biologic marker for outcome.

Keywords

MicroRNAMiRNAMiR-21Pancreatic cancer

Copyright information

© The Society for Surgery of the Alimentary Tract 2008

Authors and Affiliations

  • Mary Dillhoff
    • 1
  • James Liu
    • 2
  • Wendy Frankel
    • 2
  • Carlo Croce
    • 3
  • Mark Bloomston
    • 1
  1. 1.Department of SurgeryThe Ohio State UniversityColumbusUSA
  2. 2.Department of PathologyThe Ohio State UniversityColumbusUSA
  3. 3.Department of Molecular Virology, Immunology and Molecular GeneticsThe Ohio State UniversityColumbusUSA