MicroRNA Expression in Formalin-Fixed, Paraffin-Embedded Samples of Canine Cutaneous and Oral Melanoma by RT-qPCR

Area of Science:

• Veterinary Oncology
• Molecular Biology
• Biomarker Discovery

Background:

• MicroRNAs (miRNAs) are small, noncoding RNAs regulating protein expression post-transcriptionally.
• miRNAs are increasingly recognized as potential clinical biomarkers for various diseases, including tumors.
• Formalin-fixed, paraffin-embedded (FFPE) tissues are valuable for retrospective studies but require validation for miRNA analysis.

Purpose of the Study:

• To investigate differential miRNA expression in canine malignant melanoma using FFPE samples.
• To assess the expression levels of specific miRNAs (miR-145, miR-146a, miR-425-5p, miR-223, miR-365, miR-134) in canine oral and cutaneous melanoma.
• To explore the potential role of these miRNAs in canine melanoma pathogenesis.

Main Methods:

• Quantitative reverse transcription polymerase chain reaction (RT-qPCR) with TaqMan probes was employed.
• Expression levels of six selected miRNAs were analyzed.
• Samples included oral canine malignant melanoma, cutaneous malignant melanoma, healthy oral mucosa, and healthy skin.

Main Results:

• Cutaneous canine malignant melanoma showed downregulated miR-145 and miR-365, and upregulated miR-146a and miR-425-5p compared to controls.
• Oral canine malignant melanoma exhibited downregulation of miR-145.
• Differentially expressed miRNAs may influence RAS, Rap1, TGF-β, and phosphatidylinositol signaling pathways.

Conclusions:

• miR-145, miR-365, miR-146a, and miR-425-5p are differentially expressed in canine malignant melanoma FFPE samples.
• These miRNAs show potential as biomarkers for canine melanoma.
• The identified miRNAs may contribute to the pathogenesis of canine malignant melanoma.