EBNA-1 Regulation of miRNA-155 in Papillary Thyroid Carcinoma: A Case-Control Study in Iraqi Patients

<ns3:p>Abstract* Background Papillary thyroid carcinoma (PTC) represents the most prevalent form of thyroid malignancy worldwide, with increasing incidence rates observed across various populations. Epstein-Barr virus (EBV) has been implicated in numerous malignancies, with its encoded nuclear antigen 1 (EBNA1) playing a crucial role in modulating host gene expression, particularly microRNAs. MicroRNA-155 (miR-155) has emerged as a significant oncogenic regulator in various cancers. Objectives This study was designed to investigate the involvement of EBNA1 in the regulation of miRNA-155 in PTC and to evaluate the diagnostic and prognostic values of miR-155 in Iraqi patients. Materials and Methods A case-control study was conducted involving 100 histologically confirmed PTC patients and 100 nodular goiter controls recruited from Baghdad, Iraq, between March 2024 and August 2024. Expression levels of EBNA1 and miR-155 were quantified using quantitative real-time polymerase chain reaction (qRT-PCR). Statistical analyses included correlation assessment, receiver operating characteristic (ROC) curve analysis. Results EBNA1 positivity was higher in PTC cases (82%) compared to controls (41%) (p &lt; 0.001), Both miR-155 and EBNA1 expression levels were significantly elevated in PTC cases, with mean values of 5.38 ± 2.50 and 24.3 ± 11.96, respectively, compared to controls (1.51 ± 1.25 and 15.9 ± 19.20, p &lt; 0.0001). However, correlation analysis revealed a weak negative relationship between miR-155 and EBNA1 expression (r = -0.031, p = 0.758). ROC analysis demonstrated excellent diagnostic performance of miR-155 with an area under the curve (AUC) of 0.927, sensitivity of 83%, and specificity of 87%. Conclusion EBNA1 appears to play a regulatory role in miR-155 expression in PTC, despite the absence of a direct linear correlation. MiR-155 demonstrates strong potential as a diagnostic biomarker for PTC in Iraqi patients, warranting further investigation into its therapeutic implications.</ns3:p>