Previously undescribed thyroid-specific miRNA sequences in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy, wherein diagnostic limitations and lack of accurate prognostic factors are important clinical challenges. In this study, we report the discovery of 234 novel miRNAs in non-neoplastic thyroid and PTC samples, obtained from publicly available small RNA sequencing datasets (TCGA and GEO). These sequences were observed to display similar molecular features compared to currently annotated miRNAs. These potentially novel miRNAs presented tissue-specificity and largely decreased expression in PTC compared to nonneoplastic samples. We showed that the disrupted novel miRNAs have diagnostic and prognostic potential, and were associated with BRAF mutation, a frequent alteration related to more aggressive PTC. In conclusion, our results expand the miRNA repertoire in thyroid tissues and highlight the potential biological role and clinical utility of previously unannotated miRNAs.