Differential expression and correlation analysis of miRNAs in thyroid nodule and plasma

Abstract

Objective The variation of miRNAs profiling was identified in thyroid nodule tissue and patient plasma samples, the correlation between the expression of miRNA was analyzed in thyroid nodules and plasma. Furthermore, the importance of miRNA in plasma as a marker in thyroid nodule diagnosis was evaluated. Methods Case-control method was used. 5 female patients with thyroid lobectomy in Beijing Dongzhimen Hospital were enrolled during May and July in 2015. 16 female patients with thyroid nodules by ultrasound diagnosis, also15 healthy female without thyroid nodules were recruited during the same time. miRNA array was used to identify a subset of differentially expressed miRNAs between thyroid nodule and adjacent tissue (n=5). These miRNAs were further validated by real-time RT-PCR in a cohort of 16 thyroid nodule patients and 15 healthy controls. The miRNA expression difference between patients with thyroid nodules and healthy controls was analyzed by t test analysis. The correlation of miRNA expression between thyroid tissue and plasma was analyzed by Pearson correlation analysis. Results The miRNA array identified 57 miRNAs dysregulation, including 34 upregulation ones and 23 downregulation ones(t=3.637, 3.821, 4.907, 3.383,-5.516, 4.332,-4.993, 3.980, 5.208,-2.981, 2.840, 4.945, 4.945,-2.927,-3.561,-4.665, 3.161, 3.363, 4.846, 3.834, 2.826,-3.868, 3.816, 2.802, 5.511, 3.772,-4.424, 3.420, 3.199, 4.320, 4.053, 4.997,-3.292, 5.304,-3.281,-3.262,-4.128,-2.963, 4.228, 2.949, 4.436, 2.796, 3.199,-4.636, 4.091, 3.633, 3.481,-5.344, 4.753,-3.766,-5.340, 4.888,-4.631, 5.511, 2.921,-3.042,-4.935, P 1.5) and miR-199a-5p, miR-31 are downregulated (fold change <0.6) in thyroid nodule tissue comparing with normal tissue. Their dysregulation was further validated by real time RT-PCR in plasma samples. The significant miRNAs were confirmed with miR-181b, miR-494 and miR-106a* upregulation in thyroid nodule patients plasma. And the plasma miRNA expression levels were correlated with miRNA array results according to Pearson correlation analysis (r=0.713, 0.878 and 0.751 respectively, P<0.05). Conclusion The study highlighted that miR-181b, miR-494 and miR-106a* were differentially expressed in thyroid nodule patients not only in tissue but also in plasma, which could provide potential value as a marker for early diagnosis of thyroid nodule. (Chin J Lab Med, 2016, 39: 837-842) Key words: Thyroid nodule; microRNAs; Gene expression profiling; Biological markers