Disease-Relevant Preoperative Serum miRNA Levels in Papillary Thyroid Cancer

Background: Papillary thyroid cancer (PTC) is the most common form of thyroid malignancy, with an incidence that has been steadily rising globally. Early and accurate diagnosis remains crucial for effective treatment and improved outcomes. MicroRNAs (miRNAs), small non-coding RNA molecules that regulate gene expression, have emerged as promising biomarkers in cancer research due to their stability and accessibility in serum. In this pilot study we compared the expression of 84 consistently reported, malignancy-associated serum miRNAs in patients with PTC (PTC group) and benign thyroid disease (Control group) as potential PTC markers. Methods: A focused panel containing primer assays for 84 human miRNAs that are consistently reported in the literature as being detectable and differentially expressed in serum in various organ-specific cancers was used to measure miRNA levels in serum samples from PTC (n = 8) and benign thyroid disease (n = 6) patients prior to thyroidectomy. Results: Among the 84 miRNAs analyzed, a panel of ten miRNAs showed numerical trends of differential expression between the two groups, including three upregulated (hsa-miR-150-5p, hsa-miR-21-5p, hsa-miR-23a-3p) and seven downregulated miRNAs (hsa-miR-17-5p, hsa-miR-17-3p, hsa-miR-200c-3p, hsa-miR-296-5p, hsa-miR-574-3p, hsa-miR-885-5p, hsa-miR-130-3p). The serum expression levels of hsa-miR-23a-3p were markedly elevated in patients with malignant nodules compared with those with benign lesions, while hsa-miR-574-3p was significantly downregulated in the PTC group. Conclusions: These findings warrant further investigation of hsa-miR-23a-3p and hsa-miR-574-3p in larger cohorts of patients with PTC to validate their potential clinical relevance.