[528] MicroRNA Profiles in Merkel Cell Carcinoma: Analysis Via Microarray and Novel Cloning and Sequencing Method

P Masry, N Renwick, H Feilotter, X Zhang, T Tuschl, VA Tron. Queen's University, Kingston, ON, Canada; The Rockefeller University, New York, NY

Background: MicroRNAs (miRNAs) are small, non-coding, regulatory RNAs encoded in the genome of animals, plants and insects. Dysregulation of miRNA expression has been observed in many diseases, including cancer. We speculated that miRNAs are dysregulated in Merkel Cell Carcinoma (MCC), and that specific miRNAs are involved in MCC pathogenesis.
Design: To address this, we began by comparing the miRNA expression profiles of MCC tumors and normal skin by using archival formalin fixed, paraffin embedded (FFPE) tissue. We have previously confirmed the validity of using FFPE tissue to profile miRNAs using an Agilent array platform (J Mol Diagn. 2008 Nov;10(6):513-9). Quantitative real time RT-PCR analysis was used to validate the microarray data. Finally, the FFPE tissue samples underwent a novel cloning and sequencing profiling method to further confirm our results.
Results: Unsupervised hierarchical clustering clearly illustrated significant differences in miRNA expression profiles between MCC and normal skin. Supervised analysis identified 5 up-regulated and 10 down-regulated miRNAs in MCC relative to normal controls. The novel cloning and sequencing profiling technique confirmed both aberrantly overexpressed and underexpressed miRNAs in MCC. Certain miRNAs appear to be of great interest in MCC, with levels of expression showing an increase in excess of 300 fold, while others were up to 500 fold decreased, as compared to normal skin.
Conclusions: Our studies suggest that miRNAs are dysregulated in Merkel Cell Carcinoma and may play a role in its initiation and progression.
Category: Dermatopathology

Monday, March 22, 2010 1:15 PM

Platform Session: Section F, Monday Afternoon


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