MicroRNA-451 as a prognostic marker for diagnosis and lymph node metastasis of papillary thyroid carcinoma.

BACKGROUND AND OBJECTIVE

To investigate the diagnostic potentials of microRNA-451(miR-451) in papillary thyroid carcinoma (PTC) diagnosis and lymph node (LN) metastasis, formalin-fixed, paraffin-embedded (FFPE) tissue specimens corresponding to PTC tumors (n= 60) and their normal counterparts (Normal tissues Adjacent to Tumor, NAT, n= 60), along with sera from PTC patients with malignant tumors (n= 70) and benign lesions (n= 70) were analyzed for the expression of miR-451 by real-time PCR.

METHODS

The usefulness of miR-451 expression as a prognostic marker for diagnosis of PTC malignancies was evaluated by Receiver Operating Curve (ROC). We reported that when compared to those in NAT, the levels of miR-451 in FFPE tissues from various stages of PTC patients (n= 60) were significantly lower (Mean ± SEM; 12.62 ± 1.73 vs 38.8 ± 3.51, p< 0.0001). Receiver operating curve (ROC) analysis revealed that the area under curve (AUC) was 0.808; suggesting miR-451 expression was a reliable tissue biomarker for PTC malignancies. Further in depth analyses of these specimens revealed that miR-451 levels were significantly lower in PTC patients with lymph node (LN) metastasis than those without LN metastasis (3.96 ± 1.67 vs. 14.15 ± 1.95, p= 0.006) with calculated AUC of 0.792, supporting the notion that miR-451 expression was also a good indicator for PTC lymph node involvements. Analyses sera from the cohorts of PTC patients indicated that miR-451 levels in patients with malignant lesions (n= 70) were significantly lower (10.72 ± 1.52 vs. 19.28 ± 2.73, p= 0.010) than those with benign ones (n= 70). Parallel analyses of serum miR-451 levels in patients with LN metastasis also showed that they were significantly lower when compared to those without LN metastasis (6.79 ± 2.29 vs. 12.08 ± 1.86, p= 0.017).

RESULTS

ROC analyses revealed that AUC was 0.626 for malignancies and was 0.690 for lymph node involvement, respectively, suggesting that miR-451was a modest blood based biomarker for PTC malignancies and lymph node metastasis.

CONCLUSIONS

We concluded that miR-451 expression is a reliable FFPE tissue biomarker for PTC malignancies and it may have potentials to become a noninvasive, blood-based biomarker for PTC diagnosis and evaluation of LN status.