OR09-6 Identification of MicroRNAs Critical to the Lymph Node Metastatic Process of Thyroid Cancer

The identification of thyroid tumors with the potential for poor evolution is a major concern, as current management can range from simple active surveillance to aggressive therapeutic measures. MicroRNAs are small non-coding RNAs that play a key role in the regulation of gene expression and therefore in the pathogenesis and progression of different types of cancers. Here we employed several bioinformatics tools to investigate deregulated miRNAs in the lymph node metastasis (LNM) of two different types of thyroid tumors. Using thyroid cancer RNA-seq data available on Gene Expression Omnibus (GEO), we identified 14 common deregulated miRNAs in LNM of both medullary and papillary thyroid carcinomas, three of them still negatively deregulated when compared to their respective primary tumor: miR-199a-3p, miR-199a-5p, and miR-148a-5p. Public data available on TCGA confirmed the downregulation of miR-148a-5p in LNM and tumors with advanced AJCC stage. Looking at their predicted target genes, ITGA3, PVRL1 (also called NECTIN1), SNN, and FBXO28 genes were confirmed as positively deregulated in LNM papillary thyroid carcinomas when compared to normal tissues. Public data available on TCGA once again confirmed higher expression of the ITGA3 gene in LNM, larger and invasive tumors (T4a), and stage III and IV. Similar results were observed for PVRL1 (NECTIN1) and FBXO28, but not for SNN. These bioinformatic analysis findings suggest that miR-199a-3p, miR-199a-5p, and miR-148a-5p dysregulation, leading to epithelial-mesenchymal transition and cell adhesion failure, are associated with thyroid tumors’ LNM. Presentation: Saturday, June 11, 2022 12:45 p.m. - 1:00 p.m.