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Published on: August 23, 2019
Expression of EBNA1 and miR-155 in Papillary Thyroid Carcinoma: A Case-Control Study in Iraqi Patients
Ahmed Salman1, Mothana Khalil1, Arkan Al-Esawi2
1Microbiology, Al-Anbar University/ College of Medicine, Ramadi, Al-Anbar, 1111, Iraq.
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) proposed to modulate host gene expression, particularly microRNAs, in some of these contexts. MicroRNA-155 (miR-155) has emerged as a significant oncogenic regulator in various cancers.
Objectives:
This study was designed to investigate the expression of EBNA1 and miR-155 in PTC and their association with one another, and to evaluate the diagnostic value 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); EBNA1 protein expression was additionally assessed by immunohistochemistry (IHC). Statistical analyses included correlation assessment and receiver operating characteristic (ROC) curve analysis.
Results:
EBNA1 IHC positivity was higher in PTC cases (82%) compared to controls (41%) (p < 0.001). Both miR-155 and EBNA1 mRNA 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 < 0.0001). However, correlation analysis between miR-155 and EBNA1 mRNA expression levels revealed a weak negative relationship (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 and miR-155 are each independently elevated in PTC compared with benign nodular goiter, but their expression levels do not correlate, indicating that these two markers should be interpreted as independent findings rather than evidence of a direct regulatory relationship. MiR-155 demonstrates strong potential as a diagnostic biomarker for PTC in Iraqi patients, warranting further validation in prospective, multi-center cohorts.

