MicroRNA expression in melanocytic nevi: the usefulness of formalin-fixed, paraffin-embedded material for miRNA microarray profiling

J Invest Dermatol. 2009 May;129(5):1219-24. doi: 10.1038/jid.2008.347. Epub 2008 Nov 13.

Abstract

MicroRNAs (miRNAs) are small, noncoding RNA molecules that regulate cellular differentiation, proliferation, and apoptosis. MiRNAs are expressed in a developmentally regulated and tissue-specific manner. Aberrant expression may contribute to pathological processes such as cancer, and miRNA may therefore serve as biomarkers that may be useful in a clinical environment for diagnosis of various diseases. Most miRNA profiling studies have used fresh tissue samples. However, in some types of cancer, including malignant melanoma, fresh material is difficult to obtain from primary tumors, and most surgical specimens are formalin fixed and paraffin embedded (FFPE). To explore whether FFPE material would be suitable for miRNA profiling in melanocytic lesions, we compared miRNA expression patterns in FFPE versus fresh frozen samples, obtained from 15 human melanocytic nevi. Out of microarray data, we identified 84 miRNAs that were expressed in both types of samples and represented an miRNA profile of melanocytic nevi. Our results showed a high correlation in miRNA expression (Spearman r-value of 0.80) between paired FFPE and fresh frozen material. The data were further validated by quantitative RT-PCR. In conclusion, FFPE specimens of melanocytic lesions are suitable as a source for miRNA microarray profiling.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cryopreservation
  • Female
  • Formaldehyde
  • Gene Expression Profiling / methods*
  • Gene Expression Regulation, Neoplastic
  • Histocytological Preparation Techniques
  • Humans
  • Male
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Middle Aged
  • Nevus, Pigmented / genetics
  • Nevus, Pigmented / metabolism*
  • Oligonucleotide Array Sequence Analysis / methods*
  • Paraffin Embedding
  • Skin Neoplasms / genetics
  • Skin Neoplasms / metabolism*

Substances

  • MicroRNAs
  • Formaldehyde